Cold starting
Mountain Pass
Joined: Dec 2003
Posts: 151
Likes: 2
From: Hendersonville, NC
It's generally accepted practice to run the switched line positive and negative straight to ground. If I'm reading you right what you have there should work, but make sure that only one large (contactor) terminals has power while not activated.
I'm not sure where the solenoid coil (not the contactor) power feed comes from but if it isn't fused it should be. An indicator light is highly recommended with hard wiring, and that line should be pulled straight off the heavy terminal and fused appropriately of course.
I'm not sure where the solenoid coil (not the contactor) power feed comes from but if it isn't fused it should be. An indicator light is highly recommended with hard wiring, and that line should be pulled straight off the heavy terminal and fused appropriately of course.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,354
Likes: 5,946
From: Lake Hartwell, GA
Greasemonkee brings up a good point about wiring up a light to the GPR so you can see and confirm 100% that it is on or off. I used the link and write up below to install a GPR LED in my dash bezel.
https://www.ford-trucks.com/forums/7...wmriceman.html
In addition, you mentioned a switch. You may want to consider a momentary switch that is NO (normally open) and when pressed and held it is closed. I used a large NO momentary switch for my auxiliary fuel tank pump. This way the only time the pump (GPR in your case) is on is when you have your finger on the switch and are applying pressure.
Just some thoughts to consider...
https://www.ford-trucks.com/forums/7...wmriceman.html
In addition, you mentioned a switch. You may want to consider a momentary switch that is NO (normally open) and when pressed and held it is closed. I used a large NO momentary switch for my auxiliary fuel tank pump. This way the only time the pump (GPR in your case) is on is when you have your finger on the switch and are applying pressure.
Just some thoughts to consider...
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,354
Likes: 5,946
From: Lake Hartwell, GA
Using your very helpful diagram from post #9, I have modified it as a visual aid for installing a GPR momentary switch and GPR LED.
My changes are noted by an orange arrow and a note describing the change. Very easy, simple fix that would eliminate the ground fault within the PCM and also provide an LED to be 100% sure the GPR is off or on.
In addition to the advice provided above by the fellas, the Trombetta 684-1241-212 relay has been proven to be a more suitable replacement for the OEM GPR versus the Stancor/White Rogers GPR. The Trombetta is just as reliable, but fits in the OEM location and position.
Mountain Pass
Joined: Dec 2003
Posts: 151
Likes: 2
From: Hendersonville, NC
I grabbed a couple of those trombetta units myself - backups and spare parts are golden.
The reason for having the positive side switched is in the instance of a short to ground - then you have the solenoid stuck in the on position perhaps unbeknownst to the driver whereas a switched positive would simply blow the fuse. But, every person has their own configuration that works best for them.
The reason for having the positive side switched is in the instance of a short to ground - then you have the solenoid stuck in the on position perhaps unbeknownst to the driver whereas a switched positive would simply blow the fuse. But, every person has their own configuration that works best for them.
Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
I grabbed a couple of those trombetta units myself - backups and spare parts are golden.
The reason for having the positive side switched is in the instance of a short to ground - then you have the solenoid stuck in the on position perhaps unbeknownst to the driver whereas a switched positive would simply blow the fuse. But, every person has their own configuration that works best for them.
The reason for having the positive side switched is in the instance of a short to ground - then you have the solenoid stuck in the on position perhaps unbeknownst to the driver whereas a switched positive would simply blow the fuse. But, every person has their own configuration that works best for them.
Cargo Master
Joined: Oct 2007
Posts: 2,712
Likes: 107
From: BoCoMo
So I put in the switch to the relay and it worked. But now I got a big problem. I was warming it up and then all of a sudden the truck turns off and I go to start it again and the battery is dead. So here's how I hooked it up I took the negative from the PCM that should look like a orange wire and covered it with electrical tape. Then took new wire from that terminal to one post on the dash then with the other post wired it up to the negative on the battery.
1) push it in and see what your batteries voltage is Before you turn the key on..... over 12.5v...
2) turn key on 'wait to start' and your voltage should drop as the glow plugs come on..... around 11.5v... if glow plugs do not 'come on'... find out why??
3) when 'wait to start' light goes out, Starter will drop voltage while cranking..... around 11.v..
4) If your voltage drops below 10.5v.... your truck will not start due to lack of voltage.... (bad batteries???/you just said you had dead batts??)
5) when the truck is started the voltage will slowly go up as GPR is shut off and the voltage will settle at the output of the Alternator... around 13.5v and higher.
6) a voltage meter (pushed into the power port on the dash) will tell you a lot about what is going on with your electrical system than a 'light' being on/off
7) imo
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