GP Relay Info?
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GP Relay Info?
I'm trying to figure out the Glow Plug system. I think the plugs aren't working and am trying to figure if the relay isn't working. A book says there is a fuse for each bank of GPs. I guess thoses fuses will be after the relay. Is there a fuse before the relay that could be bad and not cause it to turn on ? Any info on the topic would be great. Thanks in advance
Post Fiend
Joined: Jun 2004
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From: Parker, CO
Get a multimeter and test to see if you are getting voltage through the relay. There is a "hot" side that always has power, and the other large terminal will show power with the key on. If there is no power with the key in the run position, then the relay is bad.
If you don't have a multimeter, you can get a screwdriver and jumper the two large terminals with the key in the run position. Let the glow plugs run for about 20 seconds or so and then attempt to start the truck. If it starts easier, then you know the GPR is bad.
If you don't have a multimeter, you can get a screwdriver and jumper the two large terminals with the key in the run position. Let the glow plugs run for about 20 seconds or so and then attempt to start the truck. If it starts easier, then you know the GPR is bad.
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From: South Dakota
You could have a bad GPR. 2 ways to check the relay. Option 1 When it it cold jumper the 2 big post and see how it starts. Option two is turn the key to Start and measure the voltage on the large stud with two wires wire and you should have battery voltage, if not check the other post to make sure you have battery voltage. To check the glow plugs disconnect the connector at the valve cover. The four large pins are for the glow plugs. Ohm them out, anything from .1-2 ohms is good. The P/N for the glow plugs are Motorcraft ZD-11. I found Autozone had the best deal, as for the relay NAPA GR 109 I think is the relay for it. Just have to turn it around to fit
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Hey, I just tried jumping the two smaller post with the key off and nothing happend-to be expected. Then jumped them with the key in the on position and the relay clicked on...what does that mean...I know that the PCM is putting voltage to one of the sides, but what is that saying that once the small post are jumped and the relay clicks?
I do have voltage to the big post-jumped those as well
I do have voltage to the big post-jumped those as well
Laughing Gas
Joined: Feb 2006
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Here is a link from a thread about half way down the first page. One of the posts have a pic in it.
https://www.ford-trucks.com/forums/5...n-the-gpr.html
https://www.ford-trucks.com/forums/5...n-the-gpr.html
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Cargo Master
Joined: Aug 2003
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From: Eastern Washington
Aha! My pointer thingy to the rescue!!
Please note, pointer is actually showing the AIH wire and relay, the GPR is the one further back.
Lemme see if I can catch up on this thread...
Make sure to test for voltage when the engine is cold, a hot engine won't switch on the glow plugs and you'll think your relays not working.
DON'T short out the two small terminals, that bypasses the relay and sends 12v straight to your computer. One of the small wires has 12v with ignition on, the other is a switched ground when the computer thinks you need the glow plugs on.
One large terminal should have battery voltage all the time. The other large terminal is for the glow plugs and only has voltage with the key on and a ground signal from the computer.
If you want to jump it to get it started go between the two large terminals for 30-90 seconds (if it's really cold). This is pretty poor for troubleshooting but can woork in a pinch. A better option would be a test light, an even better one would be a multimeter.
New User
Joined: Jun 2005
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Identiy
Can someone please tell me what the plastic piece above the GPR with the green and red hoses attached to it and also the green connector is? (reffering to the previous picture in previous post.)
When I turn the key on this unit makes a clicking sound.
When I turn the key on this unit makes a clicking sound.