Hands down the best video out there! I want to book a class with this man doing the instruction!! Sure I still have questions but this video was a 10 out of 10!!
Hi Pete. Good video. I am older than you and know why you say "solenoid", but I quit calling the coil in the relay a solenoid after my electronic engineer son explained to me that a solenoid (as on a starter) is a electromechanical actuator that performs work, whereas the coil inside a relay only transmits current. Keep up the good work.
You make it so E-Z to understand on how to troubleshoot the a/c I would've never known how to diagnose it like u just explained. Thank very much . I would love to have that tester tool u used on this video,any Hints where I might get my hands on one? Thanks again for this video,very helpful to me. *****
Now I have high pressure on the low pressure port of my ac system could that be my high pressure switch gone bad? And would this cause my clutch not to engage? 1999 Ford Mustang.
Great video!!! I have a 2000 Cadillac Deville I had a shop fill it with refrigerant now the clutch wont engage. Relay is good, low pressure switch read 5v with ignition forward but not running high pressure switch read 5v as well. When the clutch is jumped it blows super cold air. When the low pressure switch was disconnected the ac controls automatically disabled the ac to the off position. Any help would be appreciated.
Great video Pete. Couple of questions - 1) On the solenoid side of the tool what does it mean when the bottom LED glows red or green?2) If the bottom LED light lights - does it mean that the solenoid circuit is working as it should and the PCM is commanding the relay on? Thanks
+mrghiax 1) The same as the change in color for the top LED - the polarity of the circuit, or which terminal on the front of the tool is the switched system voltage. 2) It only indicates that the PCM has closed the circuit. I guess it is possible to have an issue with voltage drop that would still allow the LED to light but would expect that to be a rare occurrence.
I have a 2001 Ford Mustang 3.8l V6. AC started blowing hot air. I checked freon and levels are fine. Compressor is not cycling when AC is on, but when I go to turn it manually it isn't frozen. Also checked both fuses for AC and they were fine as well. Still trying to figure out what's going on
What if there isn't any power to the pressure switch on the dryer. Should there be power there when the ac is turned on? Im thinking that the control module on dash is done.....? Tyty
If your test results indicate that the ECM is not turning on the relay, then a possible cause is the lack of any sensor input it needs to OK the A/C. As for how the sensor is wired, you'll need a schematic to determine that for the vehicle you're working on.
@@MotorAgeMagazine I've swapped out the horn relay and the horn works flawlessly with both relays. I'm thinking the pcm has fried in a funny way that soldered it closed creating a parasitic drain on the batterie as the clutch stays engaged overnight without the ignition switch on
@@johnsonandson7772 If the driver that controls the relay is closed all the time, you'd have the same effect. Not as common but certainly a possibility. Install a test light across the switch side of the relay and see if it lights up. If you do find the problem is in the PCM, be sure to check to see what else that driver may control and there is no high current draw present that might have caused the damage - or you'll have the same problem down the road.
@@johnsonandson7772 Yes, the PCM activates the relay by closing the circuit of the relay solenoid on the ground side. The "switch" is referred to as a "ground side driver". However, this circuit only has power when the key is in the Run position - so it isn't likely to be the cause of a parasitic drain. Let's start at the beginning... Remove the A/C compressor clutch relay. With the key off, use a test light to check for the presence of voltage on each relay pin in the junction box. Only one should light the test light - the one going to relay pin #30. With the key ON, only two should light the test light. The second pin goes to relay pin #86 and supplys power to the relay solenoid. Let me know what happens.
.2000 Jeep Cherokee... Wont Take Freon... Compressor worked great in the other jeep. I start the car turn on A/C controls, Hi/max, When I unplug the ac compressor i still have power on the compressor end/plug but no power on the plug wire coming from the wiring harness. Only time that wire has power is when the ac is pluged in. Is that right?? My low pressure switch 4 ports has power on 3 out of 4 ports/slots. My high pressure switch2 ports has power on both ports . it wont take freon.. ..{update } car running ac controls on, if i unplug my low side sensor i then have a hot and ground on the high side switch instead of 2 hots but low side switch has 3 hot 1 neg. unplugged... i did test the wire thats going into that port and it has power going in the switch but no power in the port of the switch. If i hook the low side back up, again i got 2 hot ports on the high pressure switch. Even when i have 1 hot side other neg or no power on it. it still wont bridge over the clutch and when i got both sides hot and try bridge it it then will blow the big 20 amp fuse. So could my low pressure switch/connector be bad if so will that keep it from accepting freon.
One thing I did not see mentioned, was the IAT sensor. Some manufacturers (GM) , if the inlet air temperature sensor is bad or unplugged, it will default to 32f. The ECM will say "Hey!!! I am not turning on the AC, it is freezing outside".
trae heck True! There are numerous inputs the ECM must see before it allows the compressor to turn on. If it doesn't, it won't command the relay on and no current flow will be seen at all. If power is present to the relay but the circuit is not being completed by the ECM, it's time to check all the inputs to see what is missing. Thanks for the comment.
Great instructions thanks for the tips. I am in American Samoa and had enjoyed your great training I have a Nissan trck 2004 how do I get the wiring diagram for it.
wally Bryce You can subscribe to any of the aftermarket service information services (Mitchell 1also has a DIY service) or directly from Nissan on the OEM service site. A list of all the OEM sites can be found at www.nastf.org
I'm a beginner. 03 jeep liberty. I know I have the right refrigerant pressure. And the clutch compressor is good. I tried to bypass the relay and clutch didn't engaged. I tried to bypass the low pressure switch a and clutch didn't engaged? What should I do next? Or what does this mean? The pressure is right and clutch it's good?
So I am able to measure voltage at the compressor connector, ruling out relay, fuses, pressure switch. So clutch coil is bad? What can I measure on the clutch coil pins to determine if it's good/bad? What about A/C clutch diode? Is the diode embedded in the clutch coil, or connector? Where can I measure to determine good/bad A/C clutch diode?
George Schissel Measuring voltage at the compressor doesn't prove anything yet. Many models ground the compressor, rather than supply power, so double check the schematic. If it is power supplied, put your meter in amps mode, and check current through the field coil. 3-5 amps is typical of a field that is OK. HTH!
I have access to a few different service information providers. This one is Mitchell 1's ProDemand. For DIYers, Mitchell offers access to the same information on a "per vehicle" basis at www.eautorepair.net. Another popular source among professionals is Alldata, and they also offer a DIY version at www.alldatadiy.com/
A/C in my fiance's '08 civic works great upon first starting the car. Only after it warms up does the clutch shut off and remains off till the engine cools down. Could this be a pressure or thermostat related issue?
Adam Agee The A/C is controlled by the engine management computer, or ECM. It is possible it is seeing something it doesn't like and is turning the system off in response. I would monitor/record the engine operating parameters related to the A/C system (as found in the service information for your vehicle) at the time of failure to see what is out of whack. It may be related to engine temperature - a thermostat issue or a fan that's not coming on when it should, for example. Or an A/C pressure issue - too high, too low, or a sensor that is misreading and lying to the ECM.
Wouldn't it be easier to use a multimeter and measure the voltage going into the compressor with and without the AC switch on? You get 0Vdc with the AC off and 14Vdc with the switch on. Would that not automatically rule out the switch/relays without all of the other tests? I'm asking because I currently am having problems with my AC Clutch engaging on my 97 B4000 and don't have all of the other fancy equipment so I just tested the voltage going into the Compressor.
Justin Frady On some vehicles you can do a voltage check directly at the compressor. On others, the compressor is buried deep in the engine compartment. Using current allows you to check the compressor clutch coil operation no matter where the compressor is located.
If the clutch assembly is available separately, repair shouldn't be too much. If the entire compressor needs to be replaced - that's a bit more involved. Of course, it depends on your make/model/year of vehicle.
There are a few possibilities. The relay may be stuck in the closed position, or the ECM thinks you want the A/C on when you don't. That could be an HVAC control head switch that isn't working properly.
I have a 2001 Honda Accord my a/c compressor seems go into motion and start when I turn the a/c on, but I recently filled it up with antifreeze so I can get a cool breeze from my a/c vents but its just spitting out hot air.. any ideas on what could be going on?
+David Huerta if you actually used antifreeze, that's going to be a problem. But assuming you meant that you used R-134A, if it's still blowing warm air it likely means that the compressor isn't engaging. This can be due to the compressor clutch, as demonstrated in this video, or like so many Hondas you may have a faulty clutch. Supposedly this is a major issue with Hondas.
I have a 2001 Toyota Camry, the inside fuse (under dash) pops when I turn on the ac or defrost. A/c clutch is free, relays appear to be ok, no blinking ac light. where do I look from here, any suggestions ?
rvann You'll need a Power Distribution wiring diagram to identify all the circuits that the fuse that is failing feeds. This is a short circuit diagnosis and may or may not be in the a/c clutch circuit.
Hi Pete thanks for your video but the audio seems only to work on the left channel of my earbuds noticed this in your other videos also. A great mic to sort this problem is the rode smart lav + which works great with any smart phone. m.smartlav.com. or you could bring your audio in to the free software called audacity and mix it as mono it works on Mac or PC. Keep up the good work, sandy
i have,a 1994 S10 that has an a/c problem I trying to chase down. i checked the freon charge and it shows the system is full. on any setting of the a/c switch, the compressor will not engage. trying to find the cause. does anyone know where the a/c relay is on a 1994 S10 extended cab with a 4.3 V6?
someone help ... I have 2001 xterra fuses good .. has freon ..a/c compressor only works when I bypass the a/c compressor relay .. I tried a new relay and nothing worked
Let's review what you know to this point. 1.) The compressor clutch circuit works as evidenced when you jumped the relay control side of the circuit. 2.) It doesn't work with the old relay, and it doesn't work with a new relay...so I have to think the relay is not being turned on. The ECM has to see certain conditions met, including the request for A/C from the interior climate control panel on the dash. You'll need a scan tool with enhanced OE capability to see this PIDs. OR The circuit for the relay control side is open. You'll have to perform basic circuit tests to verify the circuit's power and ground paths are intact.
did you ever figure out the provlem? my compressor also only engages when i rig a wire in place of the relay..but i switched that and the starter relay which are the same so it cant be the relay fuse
+CDYJKR You don't indicate what year, make and model car you own so I can only offer a guess. If I saw compressor engagement with no change in high or low side pressure AND the pressures were equal high to low, I would suspect a failed compressor...probably a bad reed valve internally.
+Daniel Deras I used to work in a shop that occasionally serviced Florida Highway Patrol cruisers. These guys left their air conditioning on all day long, and it was not unusual for the relay contacts to burn - causing a voltage drop issue that could result in intermittent function.
+Motor Age I have been having a similar problem with my ranger. truck has to run for about 20mins before the clutch will click on. and works great after that. any ideas if the relay cold cause that?
Use the current test described to see if the clutch coil is energized or not, regardless if the compressor has kicked on. You may have a problem with clutch air gap or some other mechanical issue.
Hands down the best video out there! I want to book a class with this man doing the instruction!! Sure I still have questions but this video was a 10 out of 10!!
Man I sure could use your help on my Escalade lol. I’ve tried everything and still no ac. You are very good at explaining the ac system etc.
Hi Pete. Good video. I am older than you and know why you say "solenoid", but I quit calling the coil in the relay a solenoid after my electronic engineer son explained to me that a solenoid (as on a starter) is a electromechanical actuator that performs work, whereas the coil inside a relay only transmits current. Keep up the good work.
Good Afternoon Pete Meier motor age Take care and have a great day 👍
Thanks 👍
From Nick Ayivor from London England UK 🇬🇧
keep rocking the tats pops! Nice video- now this DIYer can google diagram for my car and narrow down what component has failed.
amen to the video - enough said the rest of geeks who post videos need to watch this
and 'learn'
thank you
Best tech video on this topic that I've seen yet, great job.
Thank you! Glad you liked it.
My respect and thanks for teaching us personally really I appreciate it god bless you always
You make it so E-Z to understand on how to troubleshoot the a/c I would've never known how to diagnose it like u just explained. Thank very much . I would love to have that tester tool u used on this video,any Hints where I might get my hands on one?
Thanks again for this video,very helpful to me.
*****
www.aeswave.com
Very well explained. Thank you!
Now I have high pressure on the low pressure port of my ac system could that be my high pressure switch gone bad? And would this cause my clutch not to engage? 1999 Ford Mustang.
Great video!!! I have a 2000 Cadillac Deville I had a shop fill it with refrigerant now the clutch wont engage. Relay is good, low pressure switch read 5v with ignition forward but not running high pressure switch read 5v as well. When the clutch is jumped it blows super cold air. When the low pressure switch was disconnected the ac controls automatically disabled the ac to the off position. Any help would be appreciated.
Thanks buddy, you really explained so so well. Learnt so much on that video.
Thanks for the video
please i have question if the system empty i mean there is no foren in the system,Is the clutch engage with compressor?????
Thanks for the tip, very useful.
Great video Pete. Couple of questions - 1) On the solenoid side of the tool what does it mean when the bottom LED glows red or green?2) If the bottom LED light lights - does it mean that the solenoid circuit is working as it should and the PCM is commanding the relay on? Thanks
+mrghiax 1) The same as the change in color for the top LED - the polarity of the circuit, or which terminal on the front of the tool is the switched system voltage. 2) It only indicates that the PCM has closed the circuit. I guess it is possible to have an issue with voltage drop that would still allow the LED to light but would expect that to be a rare occurrence.
Motor Age Many Thanks Pete, That has cleared that up for me.
can you tell me where i can buy that neat little tool you used called the u activate tool
THomas Herron Sure! www.aeswave.com/uActivate-p8975.html
I have a 2001 Ford Mustang 3.8l V6. AC started blowing hot air. I checked freon and levels are fine. Compressor is not cycling when AC is on, but when I go to turn it manually it isn't frozen. Also checked both fuses for AC and they were fine as well. Still trying to figure out what's going on
What if there isn't any power to the pressure switch on the dryer.
Should there be power there when the ac is turned on?
Im thinking that the control module on dash is done.....?
Tyty
If your test results indicate that the ECM is not turning on the relay, then a possible cause is the lack of any sensor input it needs to OK the A/C. As for how the sensor is wired, you'll need a schematic to determine that for the vehicle you're working on.
Why would the switch stay on? Even with the ignition off the ac clutch is always engaged unless I pull the 10A fuse. The relay tested good
The connection between the fuse and the clutch is in the relay. Sounds like it is stuck in the closed position to me. You may want to recheck that.
@@MotorAgeMagazine I've swapped out the horn relay and the horn works flawlessly with both relays. I'm thinking the pcm has fried in a funny way that soldered it closed creating a parasitic drain on the batterie as the clutch stays engaged overnight without the ignition switch on
@@johnsonandson7772 If the driver that controls the relay is closed all the time, you'd have the same effect. Not as common but certainly a possibility. Install a test light across the switch side of the relay and see if it lights up. If you do find the problem is in the PCM, be sure to check to see what else that driver may control and there is no high current draw present that might have caused the damage - or you'll have the same problem down the road.
@@MotorAgeMagazine Would the driver be the pcm? It's a 98 dodge ram so it only really has the one brain or control module
@@johnsonandson7772 Yes, the PCM activates the relay by closing the circuit of the relay solenoid on the ground side. The "switch" is referred to as a "ground side driver". However, this circuit only has power when the key is in the Run position - so it isn't likely to be the cause of a parasitic drain. Let's start at the beginning...
Remove the A/C compressor clutch relay. With the key off, use a test light to check for the presence of voltage on each relay pin in the junction box. Only one should light the test light - the one going to relay pin #30.
With the key ON, only two should light the test light. The second pin goes to relay pin #86 and supplys power to the relay solenoid.
Let me know what happens.
.2000 Jeep Cherokee... Wont Take Freon... Compressor worked great in the other jeep. I start the car turn on A/C controls, Hi/max, When I unplug the ac compressor i still have power on the compressor end/plug but no power on the plug wire coming from the wiring harness. Only time that wire has power is when the ac is pluged in. Is that right?? My low pressure switch 4 ports has power on 3 out of 4 ports/slots. My high pressure switch2 ports has power on both ports . it wont take freon.. ..{update } car running ac controls on, if i unplug my low side sensor i then have a hot and ground on the high side switch instead of 2 hots but low side switch has 3 hot 1 neg. unplugged... i did test the wire thats going into that port and it has power going in the switch but no power in the port of the switch. If i hook the low side back up, again i got 2 hot ports on the high pressure switch. Even when i have 1 hot side other neg or no power on it. it still wont bridge over the clutch and when i got both sides hot and try bridge it it then will blow the big 20 amp fuse. So could my low pressure switch/connector be bad if so will that keep it from accepting freon.
One thing I did not see mentioned, was the IAT sensor. Some manufacturers (GM) , if the inlet air temperature sensor is bad or unplugged, it will default to 32f.
The ECM will say "Hey!!! I am not turning on the AC, it is freezing outside".
trae heck True! There are numerous inputs the ECM must see before it allows the compressor to turn on. If it doesn't, it won't command the relay on and no current flow will be seen at all. If power is present to the relay but the circuit is not being completed by the ECM, it's time to check all the inputs to see what is missing. Thanks for the comment.
Motor Age orfice tube
Great instructions thanks for the tips. I am in American Samoa and had enjoyed your great training I have a Nissan trck 2004 how do I get the wiring diagram for it.
wally Bryce You can subscribe to any of the aftermarket service information services (Mitchell 1also has a DIY service) or directly from Nissan on the OEM service site. A list of all the OEM sites can be found at www.nastf.org
how to do it without the Uactivate? is there a way?
I'm a beginner.
03 jeep liberty.
I know I have the right refrigerant pressure.
And the clutch compressor is good.
I tried to bypass the relay and clutch didn't engaged.
I tried to bypass the low pressure switch a and clutch didn't engaged?
What should I do next?
Or what does this mean?
The pressure is right and clutch it's good?
Have you verified that you have power at the clutch? How about the air gap? How much current is the clutch coil drawing when energized?
So I am able to measure voltage at the compressor connector, ruling out relay, fuses, pressure switch. So clutch coil is bad? What can I measure on the clutch coil pins to determine if it's good/bad? What about A/C clutch diode? Is the diode embedded in the clutch coil, or connector? Where can I measure to determine good/bad A/C clutch diode?
George Schissel Measuring voltage at the compressor doesn't prove anything yet. Many models ground the compressor, rather than supply power, so double check the schematic. If it is power supplied, put your meter in amps mode, and check current through the field coil. 3-5 amps is typical of a field that is OK. HTH!
Hi!
A dumb question maybe but,
if there is no pressure on the low side, is there pressure on the high side?
Thanx from Sweden ☺
+Fredrik Sundvall No, pressure will be equal on both sides with the system "off".
Hi,I have 99 vw beetle an my air compresor cluch dont relesasestill running even if I chance to hot temperature,amy idea about what wrong?
Dear Sir from where you get the diagrams?
I have access to a few different service information providers. This one is Mitchell 1's ProDemand. For DIYers, Mitchell offers access to the same information on a "per vehicle" basis at www.eautorepair.net. Another popular source among professionals is Alldata, and they also offer a DIY version at www.alldatadiy.com/
A/C in my fiance's '08 civic works great upon first starting the car. Only after it warms up does the clutch shut off and remains off till the engine cools down. Could this be a pressure or thermostat related issue?
Adam Agee The A/C is controlled by the engine management computer, or ECM. It is possible it is seeing something it doesn't like and is turning the system off in response. I would monitor/record the engine operating parameters related to the A/C system (as found in the service information for your vehicle) at the time of failure to see what is out of whack. It may be related to engine temperature - a thermostat issue or a fan that's not coming on when it should, for example. Or an A/C pressure issue - too high, too low, or a sensor that is misreading and lying to the ECM.
Motor Age Thanks for the quick response and recommendations.
Motor Age suppressor show possible fix
Wouldn't it be easier to use a multimeter and measure the voltage going into the compressor with and without the AC switch on? You get 0Vdc with the AC off and 14Vdc with the switch on. Would that not automatically rule out the switch/relays without all of the other tests? I'm asking because I currently am having problems with my AC Clutch engaging on my 97 B4000 and don't have all of the other fancy equipment so I just tested the voltage going into the Compressor.
Justin Frady On some vehicles you can do a voltage check directly at the compressor. On others, the compressor is buried deep in the engine compartment. Using current allows you to check the compressor clutch coil operation no matter where the compressor is located.
Gotcha
how much its cost of that repair ?just an estimate price
If the clutch assembly is available separately, repair shouldn't be too much. If the entire compressor needs to be replaced - that's a bit more involved. Of course, it depends on your make/model/year of vehicle.
@@MotorAgeMagazine 2003 lincoln town car executive
@@jovitosolamin268 Costs can vary depending on where you live, the shop's labor rate and price mark-up.
Blower motor is working also !
I drive a Toyota picnic 2010 and the a/c won't disengage what could be causing this. can someone plz help me
There are a few possibilities. The relay may be stuck in the closed position, or the ECM thinks you want the A/C on when you don't. That could be an HVAC control head switch that isn't working properly.
Great video thanks
I have a 2001 Honda Accord my a/c compressor seems go into motion and start when I turn the a/c on, but I recently filled it up with antifreeze so I can get a cool breeze from my a/c vents but its just spitting out hot air.. any ideas on what could be going on?
+David Huerta if you actually used antifreeze, that's going to be a problem. But assuming you meant that you used R-134A, if it's still blowing warm air it likely means that the compressor isn't engaging. This can be due to the compressor clutch, as demonstrated in this video, or like so many Hondas you may have a faulty clutch. Supposedly this is a major issue with Hondas.
I have a 2001 Toyota Camry, the inside fuse (under dash) pops when I turn on the ac or defrost. A/c clutch is free, relays appear to be ok, no blinking ac light. where do I look from here, any suggestions ?
rvann You'll need a Power Distribution wiring diagram to identify all the circuits that the fuse that is failing feeds. This is a short circuit diagnosis and may or may not be in the a/c clutch circuit.
Hi Pete thanks for your video but the audio seems only to work on the left channel of my earbuds noticed this in your other videos also. A great mic to sort this problem is the rode smart lav + which works great with any smart phone. m.smartlav.com. or you could bring your audio in to the free software called audacity and mix it as mono it works on Mac or PC. Keep up the good work, sandy
You know, I have an adaptor that splits it to the recording but didn't think about using it. I'll fix that going forward. Thanks!
Another great video Pete, thank you!
excellent but you need a better camera.😎
I have no fire going to my compressor does anyone have any idea what I can do
i have,a 1994 S10 that has an a/c problem I trying to chase down. i checked the freon charge and it shows the system is full. on any setting of the a/c switch, the compressor will not engage. trying to find the cause. does anyone know where the a/c relay is on a 1994 S10 extended cab with a 4.3 V6?
someone help ... I have 2001 xterra fuses good .. has freon ..a/c compressor only works when I bypass the a/c compressor relay .. I tried a new relay and nothing worked
Let's review what you know to this point. 1.) The compressor clutch circuit works as evidenced when you jumped the relay control side of the circuit. 2.) It doesn't work with the old relay, and it doesn't work with a new relay...so I have to think the relay is not being turned on.
The ECM has to see certain conditions met, including the request for A/C from the interior climate control panel on the dash. You'll need a scan tool with enhanced OE capability to see this PIDs.
OR
The circuit for the relay control side is open. You'll have to perform basic circuit tests to verify the circuit's power and ground paths are intact.
did you ever figure out the provlem? my compressor also only engages when i rig a wire in place of the relay..but i switched that and the starter relay which are the same so it cant be the relay fuse
My compressor engages no problem, but the pressures on the gauges don't change at all!
+CDYJKR You don't indicate what year, make and model car you own so I can only offer a guess. If I saw compressor engagement with no change in high or low side pressure AND the pressures were equal high to low, I would suspect a failed compressor...probably a bad reed valve internally.
+Motor Age it's a 2000 BMW 328i, and that's what I feared. Thank you for your reply.
what would cause a relay to work improperly . Sometimes it works sometimes it don't . If I run it direct it stays on . 1996 379 peterbilt
+Daniel Deras I used to work in a shop that occasionally serviced Florida Highway Patrol cruisers. These guys left their air conditioning on all day long, and it was not unusual for the relay contacts to burn - causing a voltage drop issue that could result in intermittent function.
+Motor Age I have been having a similar problem with my ranger. truck has to run for about 20mins before the clutch will click on. and works great after that. any ideas if the relay cold cause that?
Use the current test described to see if the clutch coil is energized or not, regardless if the compressor has kicked on. You may have a problem with clutch air gap or some other mechanical issue.
+Motor Age ok I will test the relay
BUMMER too "engineering" for me to get. I appreciate your doing a video tho! I am a 'hands on' lady...
Too technical. This is probably helpful for someone studying automotive mechanics. He lost me with all the technical details and terminology.
That looks like a Christian bros shop
chris hinckle It is. The owner is kind enough to allow me the use of his facilities for our video shoots.