Hey guys. So the truck in question is my namesake. Im about to put new motor-craft glow plugs in the beast. So i tested the voltage at the glows to be 12 volts per a fluke meter. And from what I've read here on my year truck it should be bout half that.

A little back story for you. The truck came to me sniffing ether, with supposedly new glows, injectors, return line kit. But with the previous owner continously using ether to start, who can tell if the glows WERE recently replaced. Now it also happens to be switched over to manual toggle for the glows. And I did check it to make sure the wiring was correct. It was.

So what i need to know is what does this tell me that it's getting 12 volts direct to the glow plugs? Is the GP relay or controller bad? How do i remedy this. I know it needs to be stepped down so as not to burn them out.

Thanks in advance for any information.

Travis

 

BWD GPR8 - Glow Plug Controller | O'Reilly Auto Parts

this is the part you need that should fix your problem. and your in luck. the dang thing was 144 dollars about a year ago when i bought it. yes it should be dumbed down to 6 volts from my understanding

 

Thanks for the link. And let me understand. Something on the GP controller is allowing full juice to the GP's?

Since there is already a manual toggle switch in place I was hoping to use it. Any way to take the controller out of the loop while cutting the voltage down to what it should be?

From what I've read on this site, the manual toggle is the way to go. Gotta think it would be easier to trash the controller an use some kind of resistor or some such to cut the power down?

 

I believe that wavy metal think on the controller is the resistor. Is the wire to the glow plugs hooked to the bottom terminal on the resistor? If it were hooked to the top you'd get 12v.

 

with the decrease in price of the controller/relay setup in the link i gave you i would ditch the manual button and use the stock setup in the key switch. im not a fan of the push button for several reasons:

1. someone needs to drive your truck who doesn't know about it can:
a. crank it to long and burn up starter not knowing the stock system doesn't work
b. hold the button down to long burning out the plugs
2. more random wiring laying around to potentially get hot, melt, and cause a short circuit and possibly a fire.
3. kids i don't know about you but my buddies boy loves playing around in our trucks and if i had the button i know he would mess with it he loves turning all the ***** and buttons and such. i take my key out no worries for me about burning out my plugs or accidental starting.
4. resale value is higher if you ever decide to sell it if all factory systems work properly.

to each his own but i love my stock system. i don't have to worry about regulating it down with some homemade setup, i know when the plugs are on and off, i don't have to do any extra wiring, i don't have to worry about someone messing with the button or not using it when its supposed to be used, the system knows how long the plugs should be on so there is no unnecessary on time, and she fires every single time with 1 cycle of the plugs.

 

Well, now im questioning myself on the wiring. I will have to check again.

Completely understand the reason(s) for leaving it factory stock. However, I am a modder and I dont plan on getting rid of my tow pig any time soon. Plus as a single dad, no one else drives it. And when my keys are out of truck, the toggle does not have power to the GP's. Just my simple reasoning. I actually havent had it long enough to really know better. So YMMV is so so true on this.

Thanks all for the responses.

Travis

 

ok well if power to the toggle is cut when the key is off then it sounds like someone cut the wire from the key to the relay and attached a switch in between.... which sounds kinda stupid to me.... id identify the wire the switch is run in. if it is the wire that turns the factory controller on and off i would replace controller/relay pack and remove switch and connect wires back together then ur golden.

 

The wire itself should be the resistor. 200amp draw on a 10ga wire should get the voltage drop, but all the plugs need to work to get that