Glow Plug Relay Warning Light

Cody

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I read about this mod along time ago but today jogged my mind of it as I was letting my truck warm up after work and I watched one of my coworkers try and start his new to him 7.3 as soon as he hopped in with no luck after about 30 seconds of cranking.. waited 5 seconds and tried again :morons:


After watching him do this 2 or 3 times i felt bad enough for his starter so i walked over and asked if he needed a hand. He told me his "glow plugs must be junk." I told him to try and start it again for the heck of it. His "Wait to Start Light" stayed on for about 7 seconds, went off, and he proceeded to crank. We then had a lengthy conversation on how the WTS light was simply an idiot light and the GPs could stay active for up to 2 minutes.

I had him cycle the key count to 15 and try again, magically his truck fired. He asked me how he was supposed to know when the GP cycle was over, Suddenly the relay light popped into my head. I told him it would cost him a sausage egg mcmuffin from Mcdonalds and about 12 dollars. (for both of us of course)

After we went to McDonalds we went to the local auto parts store to buy our supplies and get started.


suplies.jpg



What you will need:

1.10-15ft 12-14g wire
2. 2 sealed eyelet connections
3. 2 butt connectors
4. A 12v led light (many different options)
5. Drill and bit for led (5/16" for the one i got)
6. Wire strippers/crimpers
7. 10mm Socket with Wrench

Once we got back to the shop I had him pop his hood and located the GPR (farthest one back passenger side of the motor)
after a quick "google" and a second with the test light to make sure i figured out what each post does on the GPR


gprelayEDIT.jpg


I than ran a wire from the "pink" post which is the output to the glow plugs to the cab where i wanted to mount the LED. You will need a 10mm socket to get the nut loose and an eyelet connection

gprelaywithwire.jpg


I chose the a pillar for both his truck and mine as we have gauge pods. I simply fallowed the boost line with a few loose zip ties.

wirefallowboostline.jpg


I then drilled a 5/16" hole in the pod, connected the wire off the GPR to the positive side of the LED and ran a ground right behind the a pillar on a bolt, pushed the LED in place, threw the gauge pod back up and tested it.


warninglight-1.jpg



With the truck sitting for about a half hour his WTS light went off in 5-10 seconds but his relay stayed on for nearly 50 seconds.

This is a very easy Mod, i did both of our trucks in about an hour and 15 minutes including getting breakfast, parts, driving out to the shop from town, taking pictures while doing my truck and cleaning up... if you have any questions feel free to pm me


Hopefully this will help with cold start issues and trying to diagnose the gp system
 
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Arisley

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Nicely done. Did mine a couple years ago. It really helps, especially when your relay goes bad. You will know it imediately when the LED does not come on.

Just remember that with an LED, it makes a difference which side goes to power and which side goes to ground. It is a diode, power only moves through it one way.
 

kampy

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I hadn't seen this before but it seems like a good idea. Would there be a disadvantage or problem with just wiring it to the WTS light instead of using a separate LED?
 

CSIPSD

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I hadn't seen this before but it seems like a good idea. Would there be a disadvantage or problem with just wiring it to the WTS light instead of using a separate LED?

WTS light can sometimes be used as an indicator that your PCM is dead...

Plus its not as simple as it sounds...

The GPR LED is very easy...
 

purpleheart350

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on the to do list. I know the WTS light is just a "recommendation" but when its cold out is it better to wait for the LED to turn off to start cranking?
 

94.5stroker

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on the to do list. I know the WTS light is just a "recommendation" but when its cold out is it better to wait for the LED to turn off to start cranking?

I did this a couple moths ago and I was wondering that this morning. Like maybe it would be best to let it run once fully til the light goes out then cycle the key and start it so that the GPs are on for a while right after starting as to give it added heat for the first minute or so til the engine starts creating heat. I wasn't sure just an idea
 

SDS97_7.3

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I did this a couple moths ago and I was wondering that this morning. Like maybe it would be best to let it run once fully til the light goes out then cycle the key and start it so that the GPs are on for a while right after starting as to give it added heat for the first minute or so til the engine starts creating heat. I wasn't sure just an idea

Yeah if its really cold out and not plugged in I will let them cycle completely then turn off and turn back on, wait another 20sec and the try to start.
 

Zaairman

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I hadn't seen this before but it seems like a good idea. Would there be a disadvantage or problem with just wiring it to the WTS light instead of using a separate LED?

That's not a bad idea, but would be a lot of work.

on the to do list. I know the WTS light is just a "recommendation" but when its cold out is it better to wait for the LED to turn off to start cranking?

I'd think the truck would start easier with the glow plugs on...
 

buschpoweredstroker

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If you don't want wire an LED, you can also watch your dash lights and when they brighten up(it's quite noticeable if you pay attention) you're glow plugs have gone out.
 

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