Added GP LED mod
Hotshot
Joined: Oct 2003
Posts: 17,791
Likes: 99
From: Ashland City, TN
dont you know switches, lights and gauges are where its at? :P
New User
Joined: Sep 2012
Posts: 12
Likes: 0
Ok just to make sure I was getting to the LED I used a jumper wire at the fuse near the GPR and went rite to the hot terminal of the battery and I had the LED. Put the fuse back in and still nothing. If I test from the positive of the battery to the terminal on the GPR that is shown in the pic I get the light on my tester meaning this is actually a ground. So could my GRP be grounding out but still alowing my truck to start and run? Or is that impossible?
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Ok just to make sure I was getting to the LED I used a jumper wire at the fuse near the GPR and went rite to the hot terminal of the battery and I had the LED. Put the fuse back in and still nothing. If I test from the positive of the battery to the terminal on the GPR that is shown in the pic I get the light on my tester meaning this is actually a ground. So could my GRP be grounding out but still alowing my truck to start and run? Or is that impossible?
Use your light tester when the truck is cold. Turn the key to run and the GPR should click. Then put probe on light tester to big lug on GPR in question. The light should come on and remain on until the relay clicks off.
New User
Joined: Sep 2012
Posts: 12
Likes: 0
It is very close to ground when using a light tester. The resistance of glow plugs are very low ~ 1.5 ohms. Sounds like the GPR is not working ...
Use your light tester when the truck is cold. Turn the key to run and the GPR should click. Then put probe on light tester to big lug on GPR in question. The light should come on and remain on until the relay clicks off.
Use your light tester when the truck is cold. Turn the key to run and the GPR should click. Then put probe on light tester to big lug on GPR in question. The light should come on and remain on until the relay clicks off.
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FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
Ok I am in the middle of doing this little easy mod. but I can't seem to get the led to work. I have a good ground near the steering wheel. good connections on the power side. But I dont have any power at that post even when the truck is in the power on postion powering the glow plugs. I noticed that the GPR is diffrent. I have a 97 does that make a diffrence The picture is from a 91? any help would be great. also does the LED need tobe grounded somewere other than to the chassis.
Posting Guru
Joined: Aug 2004
Posts: 2,417
Likes: 4
From: Braham MN
A test light will work just fine for this type of problem. If your not getting the test light to light then your not getting any power to the glow plugs.
Hook your test light to the negative terminal on the battery and with the key on touch it to either SMALL terminal. those are the control wires to the GPR. If it lights on the SMALL terminals the GPR is bad internally. If there is no light on the SMALL terminals you have a wiring issue between the PCM and the GPR.
I suspect a problem elsewhere then the GPR, they make a pretty good click when they pull in.
Diesel Rod
Senior User
Joined: Oct 2012
Posts: 103
Likes: 0
A test light will work just fine for this type of problem. If your not getting the test light to light then your not getting any power to the glow plugs.
Hook your test light to the negative terminal on the battery and with the key on touch it to either SMALL terminal. those are the control wires to the GPR. If it lights on the SMALL terminals the GPR is bad internally. If there is no light on the SMALL terminals you have a wiring issue between the PCM and the GPR.
I suspect a problem elsewhere then the GPR, they make a pretty good click when they pull in.
Diesel Rod
Hook your test light to the negative terminal on the battery and with the key on touch it to either SMALL terminal. those are the control wires to the GPR. If it lights on the SMALL terminals the GPR is bad internally. If there is no light on the SMALL terminals you have a wiring issue between the PCM and the GPR.
I suspect a problem elsewhere then the GPR, they make a pretty good click when they pull in.
Diesel Rod
Senior User
Joined: Sep 2012
Posts: 207
Likes: 0
The GRP makes no noise. and I get no glow from the light tester on the Big lug. I do get power on the main that is allways supose to be hot. But should the truck still start if the GRP is not working correctly? It fires rite up as long as its not below say 50 degrees. Could the GRP be getting just enough power to heat the glow plugs wehn its warm enough out? Sorry to sound like a noob but I am still learning about diesels. I guess I can break down and buy a ohm tester if I have to. It may be a wise investment the light probe testers are not that great for this type of testing im assumming
If I'm wrong someone jump in and correct me.
I can tell too when mine are on by the volt meter, but I like the led idea. I'm going to add one to my truck.
Thanks for the idea.................
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