Just replaced mine, 99 f350 with a whopping 66,232 miles. Bought it bran new in 2000, it's entire life has been in my steel building unless it's time to go camping lol
Everyone should note below what was missed in this video as other potential failures: what was missed was a scenario where the signal wires to the glow plug relay may not be working. If the relay does not get key on power to the red wire (one of the two smaller terminals on the relay) then this will not activate the relay. Or If the other smaller terminal wire is not grounded by the glow plug controller, the relay will not work either. The glow plug controller will ground the smaller wire when it wants to activate power to the glow plug relay to send power to the glow plugs. A break in the wire will cause the relay to be inop or a bad glow plug controller may not be signalling the relay to engergize. Just because there is no power OUTPUT on the large terminal when key is switched on does not necessarily mean its for sure the relay.
REALLY great video. I realize that this is a simple fix, and thank you for not making us "non mechanics" feel stupid for ... NOT being mechanics ! To many video creators exaggerate and inflate their greatness. I appreciate that you speak clearly without a bag of marbles in your mouth. I subscribed and look forward to more of your videos. Thank you. Nick
Thank you for the feedback, I do appreciate it! I try to make my videos easy for anyone to understand, regardless of mechanical background, so that is great to hear it is working and helping :)
Good video, you get points for not spending three minutes show us your dog or talking about the weather. My power lead terminal broke exactly as yours did. These relays do not hold up well,
Very helpful video, I have a 2001 that's had trouble starting when its colder, the glow plugs were replaced only 2 years old, but I will test the voltage on the relay out and see if it solves problem. Thanks!
This right here is a great video. You were very detailed and explained everything so well. This will definitely help me out with my 02 7.3! Thank you so much.
Sits on bare metal no rubber as the relay is grounded by the bottom metal plate making good solid contact with the engine. Nothing should be in between the relay and the block or the relay won’t be grounded and therefore will not conduct electrical current. Stay safe and unhook those negative cables from the batteries.
Just to confirm the relay was dead, shouldnt you have also checked for command power coming in to the relay via the small terminals? It could keep you from replacing a GPR that isnt dead.
Always want to check power and ground on the control side as well. PCM grounds the coil, so one small terminal should have power all the time, the other should be grounded when the key is turned on. Should always verify before firing the parts cannon.
Common failure. Electrical resistance most often manifests as heat. Heat kills components like that relay. Ford often switches those with a negative connection so if you wire a manual glow switch run it from the negative leg.
How are you buddy? I have a question for you... On one side of the relay (HOT)I get 12.6V but on the other side once I turn the key it only give me 10.6V why is that? Is 2V different. I have not checked the Glow plug yet! Thank you...
Same thing happen to my 7.3 2000 Went and got a new one in the truck came back change the relay and I don’t have 12 volts on the other side what else should I check ?
I just bought a new relay and it was alot taller like whatever that thing next to the relay is. It has different threading for the bigger bolts but the box says 12v relay... my truck starter but then it didnt for a couple cranks. I moved it around a little along with the other relay lookin thing and it moves alot like it's not bolted down, then and it started. I'm confused
Have a ‘99, with 450,000 mi… sometimes hard to start, especially in cooler weather… is the glow plug relay a gradual fail or all/or nothing? Have often had to cycle the glow plugs several times to get it to start and sometimes have to use ether(I know I know)….so what is more likely: the relay or the plugs, or both? Or operator error….?
You can test the GPR using my process in the video, try that. Do you have a block heater? Try that as well in the cold and see if it helps. If it does, relay or glow plugs could be dying. Also, batteries could be losing cranking power if they're old. GPR is a relatively cheap part, so you could just replace it and see what happens too.
Justin the constant power to my relay is only reading 9 volts.. the battery is reading 12. I put the truck into the on position and the other terminal had a 0 reading. This is a bad relay correct? Just double checking! Great video
Are you talking about the 2 smaller terminals on the GPR? Yes, I should have shown and tested that as well for a complete test. But, I didn't think about it at the time because my problem was immediately apparent.
My original GPR is taller and has anti vibration feet that are straight across from each other, not at a 45 Degree ...and I do no have that 2nd component you have. Any thoughts on that? I'm original owner with 483k
Great video; thank you. Just to be sure, there is no polarity on that relay; the post with constant power could be either side/ copper post, correct? In other words, either way/ direction I install it will be correct? I purchased a Western Plow 4 post relay from Amazon( part #684-1221-212) because I have been told they are much more durable than the Motorcraft relays. Thanks!!
Sure no problem. I think you are correct with the direction/polarity. I just put mine back together the exact way I removed it with the same wires. I looked at that GPR as well but since this was the first one I've replaced I thought I'd go with OEM and see how it lasts.
tested it like you did. have 12v at the battery terminal nothing on the glowplug side with key on. replaced relay with motorcraft relay. still get the same thing. doesnt ever get power to the glow plug leads
Just opened the hood of my 2002 f250 7.3 and I do not have this relay. I have that front one you point out in the video but this one is not there. I'm not sure why my truck is different than yours?
@@TheBTRGarage even soaking it for a few days doesn't seem to help. Idk if it's somehow melted together, but I think my only option is doing some electrical wiring now
Yes, that is what mine was doing and kind of how I figured it was bad. I'd let the wait to start light run it's cycle then wait even longer. Still nothing would work. Testing it like I showed is the best way to find out if the GPR is good or bad.
I just read in another diagnostic manual that the WTS light will come on with each key turn regardless if the PCM turns on the glow plugs. This seems nuts to me.
I don't think this guy knows how a glow plug relay even works at all because that did not explain how it works and also did this guy know that your diesel ignites from the heat of the compression
This guy does know these things. This shows you how to test and replace a GPR, pretty accurately. You are welcome to provide any corrections or recommendations....
@@TheBTRGarage call just figured you would have mentioned that the PCM after checking the temperature of the oil the PCM sends a ground to the little wire there on the glow plug solenoid and that's what actuates it since it already has a constant heart then you put the key forward another little wire hot and then the PCM grounds the other little wire is how that
@@ericrkell4073 I see where you are coming from with regard to PCM controlling the GPR, but the gist of this video was replacing the relay. Yes, for completeness the author could have added in that the way the GPR gets activated is 12 volts applied switched on by the PCM to the smaller terminal (the one closest to the firewall). The PCM checks the engine oil temp and barometric pressure and decides if the glow plugs are needed. If they are 12 volts is applied and the relay fires and the glow plugs get power.
Just replaced mine, 99 f350 with a whopping 66,232 miles. Bought it bran new in 2000, it's entire life has been in my steel building unless it's time to go camping lol
Reference your name
Good job. Right on!!!!!
I have never seen a 7.3 engine bay that clean and free of oil everywhere lol. Kuddos. Thanks for the video, well done.
Thank you! It's not quite that clean anymore these days :D
I wish so bad that I would have watched this before paying a garage to do it for me. That was so simple. Great video!
Great video. Im still on my original GPR. 23 YEARS OLD. Had truck since new. 100,000 miles.
Nice, that one sounds like it is holding up good 👍
Everyone should note below what was missed in this video as other potential failures:
what was missed was a scenario where the signal wires to the glow plug relay may not be working.
If the relay does not get key on power to the red wire (one of the two smaller terminals on the relay) then this will not activate the relay.
Or
If the other smaller terminal wire is not grounded by the glow plug controller, the relay will not work either. The glow plug controller will ground the smaller wire when it wants to activate power to the glow plug relay to send power to the glow plugs. A break in the wire will cause the relay to be inop or a bad glow plug controller may not be signalling the relay to engergize.
Just because there is no power OUTPUT on the large terminal when key is switched on does not necessarily mean its for sure the relay.
Thanks for filling in the blanks! Good info 👍
Where is the controller on an engine like this? Mine has this relay but i dont spot the controller anywhere
11:33 that's the sound we ALL like !!
By the way, I have a 2001 7.3 f350 with 400,000 miles and going strong.
REALLY great video. I realize that this is a simple fix, and thank you for not making us "non mechanics" feel stupid for ... NOT being mechanics !
To many video creators exaggerate and inflate their greatness. I appreciate that you speak clearly without a bag of marbles in your mouth.
I subscribed and look forward to more of your videos.
Thank you. Nick
Thank you for the feedback, I do appreciate it! I try to make my videos easy for anyone to understand, regardless of mechanical background, so that is great to hear it is working and helping :)
Excellent description. My truck isn't starting and I just purchased 2 new batteries. I'm gonna check my relay next. Thanks for the info.
You're welcome! Glad the video could help.
Great videos Justin.. Great lighting, good clear camera views (IN FOCUS) and you explain the procedures excellent.
Thanks!
Same exact thing happened to me, GPR went bad and when taking it apart the glow plug side post snapped off. Great video keep em coming
Good video, you get points for not spending three minutes show us your dog or talking about the weather. My power lead terminal broke exactly as yours did. These relays do not hold up well,
Thanks!
I got a code on my buss for low voltage on both banks so I figured this had to be it and sure enough, dead as a door nail. Thanks for instruction.
Ooh nice that you got a code. I never had any indication other than rough/no starts. Glad to help!
thanks very much, helped me out, 2002 7.3 now starts in north idaho!
Awesome!
Very helpful video, I have a 2001 that's had trouble starting when its colder, the glow plugs were replaced only 2 years old, but I will test the voltage on the relay out and see if it solves problem. Thanks!
Glad to help!
Thank you for yet another helpful video, already put on my s&b and MBRP 4 in straight pipe
Awesome! Those are great upgrades, look at a tuner next!
This right here is a great video. You were very detailed and explained everything so well. This will definitely help me out with my 02 7.3! Thank you so much.
Does the relay sit on rubber boots or flush on metal
Sits on bare metal no rubber as the relay is grounded by the bottom metal plate making good solid contact with the engine. Nothing should be in between the relay and the block or the relay won’t be grounded and therefore will not conduct electrical current. Stay safe and unhook those negative cables from the batteries.
Well informed video man, and really helped me to get my truck going. Thank you.
Glad it helped!
good video man , having some starting issues with my 7.3 gonna use your video library to help fix the problem. Thank you
Hopefully the videos are helpful!
@@TheBTRGarage For sure, I just replaced the relay and the truck fired right up. I definitely appreciate the direction.
Thx for the vid. Very descriptive and easy to follow. Now I can fix my truck. ‘02 ford 7.3
Very good and extremely helpful for my 7.3, Thank you
You're welcome, glad it was helpful!
Thanks for the extremely detailed video man! Replaced my relay and she started right up!
Awesome, glad the video helped out!
this was a great share. Thank you for sharing your knowledge. Love my 1999 7.3L PS.
Glad you enjoyed it!
Great video, my relay came out just like yours- broken bolt and all. I was not surprised or anything, just prepared, thanks for the tutorial!
Glad to hear the video could help!
Keep your video’s going, very very informative! Thank you.
Thank you! I ha e a couple more truck videos coming soon 😁
Good video on 7.3 stuff!
Thanks for the help! Clear and to the point!
Glad it helped! Thanks for watching!
Thank you! Very helpful!
You're welcome, glad it was helpful!
I love the video, great job explaining it. Excellent job
Thank you!
Just to confirm the relay was dead, shouldnt you have also checked for command power coming in to the relay via the small terminals? It could keep you from replacing a GPR that isnt dead.
Yeah his GPR needed to be replaced regardless.
Always want to check power and ground on the control side as well. PCM grounds the coil, so one small terminal should have power all the time, the other should be grounded when the key is turned on. Should always verify before firing the parts cannon.
I just did this too 👍👍👍
Common failure. Electrical resistance most often manifests as heat. Heat kills components like that relay. Ford often switches those with a negative connection so if you wire a manual glow switch run it from the negative leg.
How are you buddy? I have a question for you... On one side of the relay (HOT)I get 12.6V but on the other side once I turn the key it only give me 10.6V why is that? Is 2V different. I have not checked the Glow plug yet! Thank you...
Excellent thanks Justin
No problem, hopefully the video helped!
Keep doing the good stuff buddy. Cheers,
Thanks, will do!
Awesome video, very well made and helpful
Thanks! Glad it helped!
So what is the relay in front of your glow plug relay?…is a glow plug relay and glow plug control module the same thing?
That other relay is for the air intake heater.
Excellent
What is the other relay in front of the glow plug relay?
The best video ever .thanks god bless you
Most welcome 😊
Why loosen the ground wire to replace the GPR instead of the hot wire?
Same thing happen to my 7.3 2000 Went and got a new one in the truck came back change the relay and I don’t have 12 volts on the other side what else should I check ?
Great video 🔥
Like the video explains very well
I just bought a new relay and it was alot taller like whatever that thing next to the relay is. It has different threading for the bigger bolts but the box says 12v relay... my truck starter but then it didnt for a couple cranks. I moved it around a little along with the other relay lookin thing and it moves alot like it's not bolted down, then and it started. I'm confused
Have a ‘99, with 450,000 mi… sometimes hard to start, especially in cooler weather… is the glow plug relay a gradual fail or all/or nothing? Have often had to cycle the glow plugs several times to get it to start and sometimes have to use ether(I know I know)….so what is more likely: the relay or the plugs, or both? Or operator error….?
You can test the GPR using my process in the video, try that.
Do you have a block heater? Try that as well in the cold and see if it helps. If it does, relay or glow plugs could be dying. Also, batteries could be losing cranking power if they're old. GPR is a relatively cheap part, so you could just replace it and see what happens too.
Ok. One of the relay hold down nuts rusted and the bolt is spinning. Easiest way to get it out?
Old one looks like an OEM relay.
The post on mine is broken too.
Good job
Autozone $54, Oreilly's $54, Advanced Auto $24, NAPA $19.99
Thank you.
You're welcome!
Justin the constant power to my relay is only reading 9 volts.. the battery is reading 12. I put the truck into the on position and the other terminal had a 0 reading. This is a bad relay correct? Just double checking! Great video
That's what it sounds like.
My solenoid smoked is it bad I do have power going to it and no power when key is off and power going to both when key is on
Was your check engine light on? Did you have any error codes (I currently have p0671, p0673, p0675, p0677)
No CEL and no codes.
My check engine is on with p0381 code. Did you get your fix? Please help
@@kemonary most likely a short somewhere, or a loose wire
Thank you sir
Welcome! Hope it was helpful.
What about signal for relay on from ignition.. ?
Are you talking about the 2 smaller terminals on the GPR? Yes, I should have shown and tested that as well for a complete test. But, I didn't think about it at the time because my problem was immediately apparent.
Great video, did you have check engine on. Mine did with p0381. Do you think this is the problem? TIA
Thanks! I did not have a CEL when I had this problem, just the issues with starting the truck.
Why don't you check the signal wire to make shore it's coming in from ignition
Tengo una Ford f250 y no la puedo Aser prender crema que son los precalentadores porque ase como que va ensender pero no ase la última función
My original GPR is taller and has anti vibration feet that are straight across from each other, not at a 45 Degree ...and I do no have that 2nd component you have. Any thoughts on that? I'm original owner with 483k
What year is your truck? Could be variations of them between years.
2002, @@TheBTRGarage
Great video; thank you. Just to be sure, there is no polarity on that relay; the post with constant power could be either side/ copper post, correct? In other words, either way/ direction I install it will be correct?
I purchased a Western Plow 4 post relay from Amazon( part #684-1221-212) because I have been told they are much more durable than the Motorcraft relays.
Thanks!!
Sure no problem. I think you are correct with the direction/polarity. I just put mine back together the exact way I removed it with the same wires. I looked at that GPR as well but since this was the first one I've replaced I thought I'd go with OEM and see how it lasts.
Great video Justin - what did you end up using to replace the dried-out boot that cracked on the power line going into the relay (6:00 in the video)?
Thanks! I was not able to find anything to replace that little boot, unfortunately. I did put a small rubber cap over the bolt head, that's about it.
tested it like you did. have 12v at the battery terminal nothing on the glowplug side with key on. replaced relay with motorcraft relay. still get the same thing. doesnt ever get power to the glow plug leads
Ouch, sounds like you have a wiring issue. Might have to trace them back starting at the GPR leads and see if you find anything.
Just opened the hood of my 2002 f250 7.3 and I do not have this relay. I have that front one you point out in the video but this one is not there. I'm not sure why my truck is different than yours?
ImAnOtter you probably have a glow plug control module. California emissions I believe. Google it for pics.
I’m changing my glow plug module soon and want to know whether or not I need to use a memory saver on my 15’ ram while the battery is disconnected.
Not sure on the Ram, my guess would be no.
Good video
Thanks!
Owesome video👍
tks video
Am I supposed to have power to all 4 terminals on glow plug solenoid
No. One small is ground the other small is the trigger. One large is constant the other large is only powered when the trigger is getting power.
same thing happened to mine. how did you fix it? I'm struggling to get the nut loose
One of the GPR terminal nuts? You can use some PB Blaster to help break it loose : amzn.to/3O1MQiR
@@TheBTRGarage thanks! I'll see if I can buy some from the auto parts store
@@baltazar514 Yea they should have it, or Home Depot, Lowe's as well. Might not be PB Blaster specifically but some kind of penetrating oil 👍
@@TheBTRGarage even soaking it for a few days doesn't seem to help. Idk if it's somehow melted together, but I think my only option is doing some electrical wiring now
Oof that sucks. I know that stuff can get really hot when shorted out, my GPR was melted in places too. Good luck!
Will the light still act like it's working properly if it turns on can the relay still be bad.?
Yes, that is what mine was doing and kind of how I figured it was bad. I'd let the wait to start light run it's cycle then wait even longer. Still nothing would work. Testing it like I showed is the best way to find out if the GPR is good or bad.
@@JustinLaps ok ty for the reply.
I just read in another diagnostic manual that the WTS light will come on with each key turn regardless if the PCM turns on the glow plugs. This seems nuts to me.
How did that hot shot sticktion stuff work?
Hard to tell exactly over the long term. The truck did feel like it ran smoother after that, cold start was not quite as tough.
@@TheBTRGarage thanks!
What is the other Relay?
It's the air intake heater relay.
Is it the same for a 97 7.3?
Yes
What is the relay for in front of the gpr that you said isn't it ?
I believe that is the air intake heater relay. Do a search for "7.3 AIH relay" and should provide some info.
Wish you opened your eyes more
what happend to your bmw?
I still have it, videos on that coming soon. It's a bit different now 😁
I don't think this guy knows how a glow plug relay even works at all because that did not explain how it works and also did this guy know that your diesel ignites from the heat of the compression
This guy does know these things. This shows you how to test and replace a GPR, pretty accurately. You are welcome to provide any corrections or recommendations....
@@TheBTRGarage call just figured you would have mentioned that the PCM after checking the temperature of the oil the PCM sends a ground to the little wire there on the glow plug solenoid and that's what actuates it since it already has a constant heart then you put the key forward another little wire hot and then the PCM grounds the other little wire is how that
@@ericrkell4073 I see where you are coming from with regard to PCM controlling the GPR, but the gist of this video was replacing the relay. Yes, for completeness the author could have added in that the way the GPR gets activated is 12 volts applied switched on by the PCM to the smaller terminal (the one closest to the firewall). The PCM checks the engine oil temp and barometric pressure and decides if the glow plugs are needed. If they are 12 volts is applied and the relay fires and the glow plugs get power.
I'm not even going to attempt this. vehicle electrical is not something i want to mess with
This is about an easy repair for the system as one could imagine. Just unhook the negative battery cables and you will be fine.
@@teichholtz too bad the mechanic charged $100 for it
What does the other relay in front of the glow plug relay do?
That one is the air intake heater relay, used to heat intake air temperature in cold situations.