Testing voltage on gpr
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Fleet Mechanic
Joined: Jun 2009
Posts: 1,346
Likes: 4
From: Connecticut
Testing voltage on gpr
My truck is garaged 5 out of 7 days a week and at work On the other 2 days I plug it in at night. Coldest its been has been upper 30 s so far and no problems turning truck over. But I went to check voltage on the gpr and I get over 12 v at the always hot post and 0 at the brown and yellow post when the ignition is turned. So is the relay bad? The wts light cycles correctly.Is there a temp that I wont get voltage there? Its 56 degrees in my garage now and Im not reading any voltage at that post. I have a new relay but havent put it in for fear its not the problem. I feel a click in the relay when its turned on and feel it click off too. But I read they can still be bad even feeling that click. About 84000 miles on original.
Hook it, I'll pull it.
Joined: May 2007
Posts: 15,037
Likes: 4
From: Grand Lake, La.
Change it out. If you don't get the volts after turning the key on, it is bad. The light in the dash has nothing to do with the glow plugs, it's only a light to let you watch it go out. You can use a screw driver to ground the post together and that should fire up the glow plugs.
Hook it, I'll pull it.
Joined: May 2007
Posts: 15,037
Likes: 4
From: Grand Lake, La.
Good deal Rob. Remember, the glow plugs stay on longer then the light stays on on the dash. When it gets real cold down here, about 45*, I turn the key on and wait at least a min before I start the truck.
Thread Starter
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Fleet Mechanic
Joined: Jun 2009
Posts: 1,346
Likes: 4
From: Connecticut
Thanks Rick, I was just gonna ask that. Good to know. How low a temp will these trucks start without being plugged in? We average teens for lows but somtimes get below zero.
Hook it, I'll pull it.
Joined: May 2007
Posts: 15,037
Likes: 4
From: Grand Lake, La.
This I don't know. We don't drive around here if it gets below 30*.
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Laughing Gas
Joined: Aug 2009
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From: Belgrade, MT
10 degrees so far
The coldest I have attempted on my truck so far was 10 degree's, and it fired up but had the romps pretty bad. I have since switched to synthetic oil, and it is supposed to hit 0 here tonight, hopefully it will fire without being plugged in. Still kind of in test mode with my truck, as I have only had it since June.
Tom
Tom
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Thread Starter
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Fleet Mechanic
Joined: Jun 2009
Posts: 1,346
Likes: 4
From: Connecticut
Just opened it, looked worse then that. There wasnt any surface area without corrosion. You could feel the relay click on and off when you turned the ignition but because there was no good surface area there was never any voltage transferred to gps.