Today is October 3rd. Been without my Mazda MPV for three weeks. I bought a new radiator fan assemble thinking that was the problem for my van over heating. It did not turn on, the fans didn't. So, just a few minutes ago tried your suggestion, switch the horn relay to the AC relay and BAAM! it worked. You just saved me a ton of money. I can not thank you enough. Thank you, thank you, thank you. Greetings from Austin, TX. God bless.
I for some reason am just now seeing your comment, and just wanted to say I'm glad this helped you, my hopes with posting this video were that it would at least help somebody, as this was a frustrating issue for me! Happy to hear you found the video helpful and were able to resolve the issue, thanks for watching!
You just saved me a ton of head scratching, say nothing for time. Great job son! Thank you. I subbed. Scarcely feels adequate to your help. Looking forward to more.
Thanks, it takes hours to find this info and some info I found contradicted what you said - but I have the 2001 626. One "expert" said the cooling fan relay was in the middle for my car. (Only the dealership really knows where these things are!) My PDF of parts also lists the one on the far left as the "window defogger" or something. Just to play it safe I'm going to replace all three!
The best practices method of testing an ISO relay marked with 85-86 is coil, 30 is power common, 87 = Normally Open, 87a = Normally closed, marks on bottom next to terminals. Use a digital multi meter and make 4 jumper wires 6-8” long. Remove relay, connect jumper wire so it can operate normally, then attach meter leads to 30 & 87, turn DDM on Vdc and watch for voltage drop across burn’t, inside terminals. A good reading is 0.080 vdc or less, re-try 6 - 9 times, open/closed. If one time it reads 1.23Vdc or more, it’s bad for sure. Swapping is an emergency testing a best as relays that operate fans, coils, etc. have a clamping diode inside while the rest use resistor in parallel with coil, so ECM/PCM can test it for OBD-II. Different relays for a purpose plus 20A, 30A, 40A who knows, but get this rating wrong and life will be short. Many good voltage drop videos as it is an auto tech best friend if you do electrical work. It was for me the last 40 years. ASE Master Tech since 1978 - Retired
Be careful changing relays around. Just because the universal terminal configuration fits the relay, the relay can be different two ways. The coil the creates an electro-magnet, has a given resistance. One may have a resistor in parallel with the coil because resistance changes with temperature or goes down. The ECM/PCM once the engine is started, starts checking components in the vehicle necessary that affect emissions. This is in done on relays using a voltage across the coil, then measures the voltage drop as the PCM either controls ground or supplies ground. A second version of relays use a clamping diode that prevent high voltage from returning into the electrical system. Commonly used in relays that control electric motors directly. A/C clutch coils can induce up to 180 volt dc and use a 1/2 watt diode installed at the compressor, tapped to the harness or in the fuse box. The other more common fan control problem used on Mazda/Fords on many models over many years. It is controlled by PWM to turn the fans on slow to fast. The relay supplies power to the fan control module only and inside the controller, they use N-Channel MOSFET(s) inside, which when turn on/off w/PWM supplies ground to the fan. A trinary switch/set pressure switch or PCM input from the A/C switch turns a PWM signal to operate fan #2 for A/C and fan #1 for the engine on most models. Yours may vary. The temperature switch for engine coolant is a NTC thermistor that has low resistance when hot, high resistance when cold. Easy to test with a DMM over a given temp range. Who knows other than published in the OEM service information +/- 5% ohms. The thermistor is sealed in a metal bulb and held in epoxy that is designed to conduct heat. NTC is the most common type. With the internet and UA-cam you can look this stuff up and watch short informative videos that did not exist when I started repairing go-carts, lawnmowers or vehicles in the late 60’s. ASE Master Tech since 1978 - Retired
So glad you found my video helpful! That was the goal haha that’s awesome! Unbelievable how much money you can save by doing it yourself and checking simple things first. Don’t forget to subscribe! Thanks for watching (:
thank you very much, i tried to take mine off today since the fan doesn't come on and it literally broke while i was trying to take it out ! just the jacket with the two-wire connected to it where it hooks on to the sensor) so i am a bit in trouble cause they dont sell the peice by itself
No problem man this problem stumped me and my father before I owned it, was a constant problem even mechanic couldn’t locate this damn thing. Crazy stuff with these cars, simple wants ya know where it’s all at!! And when you can get the part lol. Glad you found the vid helpful bro, don’t forget to hit that subscribe and turn the notification bell on! Appreciate the support
Already changed the module. $15.00 on line. But it's not working again got radiator too. Got a Mazda mpv van same modular. How about I try every relay if not marked!!! I also replaced that sensor part it's was $49 .
I am having an issue with my 2000 Mazda 626 v6. When I start the air conditioner it wont start immediately. I have to wait for a while and then the AC will start. I asked my mechanic and he told me it should be low on AC gas but I checked the gas as well and it does has enough gas. Do you think AC relay will make a difference?
Sounds like compressor may not be engaging when it should could be evap sensor or compressor clutch. Next step I’d take is to make sure the compressor is running when it’s blowing cold or if it’s not running the whole time it’s warm up until it’s cold etc to see if the compressor not running is the culprit of no cold air. If compressor is running and it takes awhile to blow cold it could be different issue.
Did you have an issue with your idle also? I noticed when the a/c is on of Im stopped the idle jumps a lot. Jw if that was an issue for you and if it fixed it.
The idle may fluctuate slightly when the AC is turned on/off. This is the compressor clutch engaging and putting a light load on the engine. If it jumps around quite a bit, and continues to do so once the AC is on you may have other issues.
I have a Mazda Protege 2.0. Coolant Fan isn't working I believe. When I unplug the temp sensor, the guage reads cold and condensor fan kicks in but not Coolant fan. Both Relays for ac and coolant fan clicks while temp sensor is unhooked. Fuse also looks good. Is there anything else I need to check before replacing the whole fan?
I have a Mazda 3, 2011, neo. For the past month or so I have noticed (several times) that the aircon fan does not start up upon turning it on. I will leave it on and drive around for a while and suddenly it will come alive. Its summers here. I took it to my mechanic, he did full service of the car; checked the air con, and it was full with gas and is perfectly healthy. He could not decipher the cause of fan malfunctioning. The fan was working fine when I took the car to him, and all the while he serviced the car. What can be the potential cause in your opinion? Thanks in advance.
Could be a bad AC relay, (on its way out), or more commonly a fan motor thats on the way out. The motor probably has a bad spot in it, and may come on while your driving due to it being moved around or jolted just enough, hence why it works intermittently. It will probably get worse over time until it no longer works completely.
Hey John! Thanks for watching - help me understand the problem a little more. When the car is hot the fans won’t turn on with the AC? Is the ac working? Blowing cold?
Helvetica Not really the AC blows out warm. When I drive the car is good when I come to a stop and in traffic the Car will overheat I had the radiator change thermostat temperature sensor and cooling fan switch and also swapped the relay to check and when I put the heater or AC both of my fans seem to Work just don’t understand why is not turning on when the car is hot and making my car overheat
Sadly from 2030 on all combustion cars including classics will be banned from public streets in entire EU and Scandinavia :-( In Germany the Green Peoples Party gave order to shorten fuel supply from 2025 on by reducing all conventional fuel stations to only one state operated central gas station per city or county. Now they even want to slow down all the gas pumps from 20 litre per minute to 2 litre per minute...From 2027 on in the EU certain car spare parts will be banned too....as exhaust systems, turbo chargers and even some engine and gearbox oils...California and New York will do the same from 2027 on.... So no investments should be done in oil burning cars any longer....They even created a new kind of crime here, called emissions and smoke crime. Called "Bundesabgasbespaßungsverbotsverordnung" in German.... :-/(((
Today is October 3rd. Been without my Mazda MPV for three weeks. I bought a new radiator fan assemble thinking that was the problem for my van over heating. It did not turn on, the fans didn't. So, just a few minutes ago tried your suggestion, switch the horn relay to the AC relay and BAAM! it worked. You just saved me a ton of money. I can not thank you enough. Thank you, thank you, thank you. Greetings from Austin, TX. God bless.
I for some reason am just now seeing your comment, and just wanted to say I'm glad this helped you, my hopes with posting this video were that it would at least help somebody, as this was a frustrating issue for me! Happy to hear you found the video helpful and were able to resolve the issue, thanks for watching!
You just saved me a ton of head scratching, say nothing for time.
Great job son!
Thank you.
I subbed.
Scarcely feels adequate to your help.
Looking forward to more.
Thanks, it takes hours to find this info and some info I found contradicted what you said - but I have the 2001 626. One "expert" said the cooling fan relay was in the middle for my car. (Only the dealership really knows where these things are!) My PDF of parts also lists the one on the far left as the "window defogger" or something. Just to play it safe I'm going to replace all three!
Great idea! Glad my video could help, there’s so much conflicting info it’s crazy!
don't give up on this channel. imma spread the word.
I wont man, gonna start making vids regularly again. thank you so much! glad you enjoyed!
Your awesome dude thank you! Only channel on UA-cam that made sense on this problem lol 10/10
Haha so glad you could find my video helpful! (: thanks for watching !!
The best practices method of testing an ISO relay marked with 85-86 is coil, 30 is power common, 87 = Normally Open, 87a = Normally closed, marks on bottom next to terminals. Use a digital multi meter and make 4 jumper wires 6-8” long. Remove relay, connect jumper wire so it can operate normally, then attach meter leads to 30 & 87, turn DDM on Vdc and watch for voltage drop across burn’t, inside terminals. A good reading is 0.080 vdc or less, re-try 6 - 9 times, open/closed. If one time it reads 1.23Vdc or more, it’s bad for sure. Swapping is an emergency testing a best as relays that operate fans, coils, etc. have a clamping diode inside while the rest use resistor in parallel with coil, so ECM/PCM can test it for OBD-II. Different relays for a purpose plus 20A, 30A, 40A who knows, but get this rating wrong and life will be short. Many good voltage drop videos as it is an auto tech best friend if you do electrical work. It was for me the last 40 years.
ASE Master Tech since 1978 - Retired
Be careful changing relays around. Just because the universal terminal configuration fits the relay, the relay can be different two ways. The coil the creates an electro-magnet, has a given resistance. One may have a resistor in parallel with the coil because resistance changes with temperature or goes down. The ECM/PCM once the engine is started, starts checking components in the vehicle necessary that affect emissions. This is in done on relays using a voltage across the coil, then measures the voltage drop as the PCM either controls ground or supplies ground. A second version of relays use a clamping diode that prevent high voltage from returning into the electrical system. Commonly used in relays that control electric motors directly. A/C clutch coils can induce up to 180 volt dc and use a 1/2 watt diode installed at the compressor, tapped to the harness or in the fuse box.
The other more common fan control problem used on Mazda/Fords on many models over many years. It is controlled by PWM to turn the fans on slow to fast. The relay supplies power to the fan control module only and inside the controller, they use N-Channel MOSFET(s) inside, which when turn on/off w/PWM supplies ground to the fan. A trinary switch/set pressure switch or PCM input from the A/C switch turns a PWM signal to operate fan #2 for A/C and fan #1 for the engine on most models. Yours may vary.
The temperature switch for engine coolant is a NTC thermistor that has low resistance when hot, high resistance when cold. Easy to test with a DMM over a given temp range. Who knows other than published in the OEM service information +/- 5% ohms. The thermistor is sealed in a metal bulb and held in epoxy that is designed to conduct heat. NTC is the most common type. With the internet and UA-cam you can look this stuff up and watch short informative videos that did not exist when I started repairing go-carts, lawnmowers or vehicles in the late 60’s.
ASE Master Tech since 1978 - Retired
Dude. Thank you so much.
I was thinking water pump (OMG NO)
Thank you for saving me hundreds of dollars. And hours.
So glad you found my video helpful! That was the goal haha that’s awesome! Unbelievable how much money you can save by doing it yourself and checking simple things first.
Don’t forget to subscribe! Thanks for watching (:
BTW, the audio was not being recorded through that iPod mic.. it didn't work out lol, but i hope the audio is good enough. thanks for watching.
Helvetica audio is A ok kid
I noticed that!😂 still a good video bro
Must be that Coolant sensor for Cooling fan.
VERY Helpful...Thanx so much !!
That is one good engine 300k on mine still going strong
Awesome information little buddy. Thanks for posting.
thank you very much, i tried to take mine off today since the fan doesn't come on and it literally broke while i was trying to take it out
! just the jacket with the two-wire connected to it where it hooks on to the sensor) so i am a bit in trouble cause they dont sell the peice by itself
No problem man this problem stumped me and my father before I owned it, was a constant problem even mechanic couldn’t locate this damn thing. Crazy stuff with these cars, simple wants ya know where it’s all at!! And when you can get the part lol. Glad you found the vid helpful bro, don’t forget to hit that subscribe and turn the notification bell on! Appreciate the support
Ill give this a shot. My protege is over heating
Lemme know how it works! If you have any questions feel free to ask as well I’ll try my best to help
thank you, I just bought a car and its over heated strait away, machanic said its got cracked head.
Very possible, but expensive repair
Already changed the module. $15.00 on line. But it's not working again got radiator too. Got a Mazda mpv van same modular. How about I try every relay if not marked!!! I also replaced that sensor part it's was $49 .
Thanks for the info bud !!
Is this the same connection pigtail for a na miata
nice comments
I am having an issue with my 2000 Mazda 626 v6. When I start the air conditioner it wont start immediately. I have to wait for a while and then the AC will start. I asked my mechanic and he told me it should be low on AC gas but I checked the gas as well and it does has enough gas. Do you think AC relay will make a difference?
Do you mean it takes a minute for it to start blowing? Or it blows immediately it just takes time to blow cold?
It does blow but it takes long time to blow cold air. But on the other end heat works perfect. And I don’t even have any overheating issue.
Sounds like compressor may not be engaging when it should could be evap sensor or compressor clutch. Next step I’d take is to make sure the compressor is running when it’s blowing cold or if it’s not running the whole time it’s warm up until it’s cold etc to see if the compressor not running is the culprit of no cold air. If compressor is running and it takes awhile to blow cold it could be different issue.
Helvetica the issue was with Air-compressor relay. I just tried changing it with Horn relay and it did work out. Thank you very much for your time.
You know your shit that's kool
Good tips!
Glad I could help!
Did you have an issue with your idle also? I noticed when the a/c is on of Im stopped the idle jumps a lot. Jw if that was an issue for you and if it fixed it.
The idle may fluctuate slightly when the AC is turned on/off. This is the compressor clutch engaging and putting a light load on the engine. If it jumps around quite a bit, and continues to do so once the AC is on you may have other issues.
I have a Mazda Protege 2.0. Coolant Fan isn't working I believe. When I unplug the temp sensor, the guage reads cold and condensor fan kicks in but not Coolant fan. Both Relays for ac and coolant fan clicks while temp sensor is unhooked. Fuse also looks good. Is there anything else I need to check before replacing the whole fan?
sKabii radiator fan switch 😏😉
Found the problem. It was the Radiator Coolant Fan Relay. It clicked but I had to tap it for the fan to come on.
Sorry i missed your question, glad you got it fixed!
I have a Mazda 3, 2011, neo. For the past month or so I have noticed (several times) that the aircon fan does not start up upon turning it on. I will leave it on and drive around for a while and suddenly it will come alive. Its summers here.
I took it to my mechanic, he did full service of the car; checked the air con, and it was full with gas and is perfectly healthy. He could not decipher the cause of fan malfunctioning. The fan was working fine when I took the car to him, and all the while he serviced the car.
What can be the potential cause in your opinion?
Thanks in advance.
Could be a bad AC relay, (on its way out), or more commonly a fan motor thats on the way out. The motor probably has a bad spot in it, and may come on while your driving due to it being moved around or jolted just enough, hence why it works intermittently. It will probably get worse over time until it no longer works completely.
Thanks bud, helped a lot!
Thanks dude!
Anytime, glad I could help!
kid your a genius. thanks a million
thank you! so glad i could help!
right information thanks
Helvetica when I turn my AC on two fan turn on but is not turning on when the engine is hot And my car will overheat
I put a brand new thermostat ,radiator ,fan switch sensor and a temperature sensor what could it be
Hey John! Thanks for watching - help me understand the problem a little more. When the car is hot the fans won’t turn on with the AC? Is the ac working? Blowing cold?
Helvetica Not really the AC blows out warm. When I drive the car is good when I come to a stop and in traffic the Car will overheat I had the radiator change thermostat temperature sensor and cooling fan switch and also swapped the relay to check and when I put the heater or AC both of my fans seem to Work just don’t understand why is not turning on when the car is hot and making my car overheat
รถสตาร์ไม่ติดเกิดจากอะไรครับ
Sadly from 2030 on all combustion cars including classics will be banned
from public streets in entire EU and Scandinavia :-( In Germany the
Green Peoples Party gave order to shorten fuel supply from 2025 on by
reducing all conventional fuel stations to only one state operated
central gas station per city or county. Now they even want to slow down
all the gas pumps from 20 litre per minute to 2 litre per minute...From
2027 on in the EU certain car spare parts will be banned too....as
exhaust systems, turbo chargers and even some engine and gearbox
oils...California and New York will do the same from 2027 on.... So no
investments should be done in oil burning cars any longer....They even
created a new kind of crime here, called emissions and smoke crime. Called "Bundesabgasbespaßungsverbotsverordnung" in German.... :-/(((
Mines a 2000 with a 4 cylinder
Wow no disrespect to u but what mechanics were u going to? There’s no way all of them would disregard looking at the relays. 🤦🏻♂️
Waste of time....."the mechanic can't fix it" he say ....that's just simple troubleshooting... what sort of mechanic he's talking about...
Absolutely!?!?!?!?!?!?!?!?!?
Nice, THx bro!