Was wondering what the white wire off the gp controller relay goes to? I wanted to try the bypass manual switch but cant fint the white wire! Mine is a 93 f250 7.3 IDI. My controller is bad and dont want to spend the $170+ for a new controller.

 

Have you tested the controller, the relay can be replaced. Email me if you need the test......

MWIF have them cheaper... http://www.mwfi.com/dieselPage/ford_73.htm

 

The white wire completes the ground to make the relay work. I took the white wire off and put tape on it. I ran another wire from the relay terminal where the white wire was, then to a push button switch, then to a good ground. The later style controllers are better, and as PLC said you can replace the relay, unless you just want the button.

 

I have tested the controller and the relay-just replaced that but looking at my set up I see No white wire? Looking at it from the front of the truck to the cab I have clockwise top left -yellow, top right -red (big), bottom right -dbl red and one single red wire, last post bottom left another yellow. I recently changed gp's a few months ago motorcraft-beru's. My wts time when cold is usually around 13 sec's. Have to plug it in every morning to start, no problem when I do that, starts right up runns great.

 

I will check mine today, and also see if I can find a picture.

 

Maybe I cant find the wire when I changed the relay but I drew the pix and colors when I did change that relay and no white wire! I've never had a problem with starting except for bad gp's and the bad relay, 256,000+ mi so far. Hate carpooling when we have to go out of town because I have a VERY hard time starting when we get back. Ultimately I always have to drive myself so I can plug in the heater. All help is appreciated.

 

If your solenoid is not working on the old relay then wiring a manual swith to operate it will not work.

I used a new single pole Motorcraft solenoid to build a manual glow plug activation system in parallel to the existing controller that I can use with a push button in case I need to glow the plugs until I can replace a burned out plug.

My 93' F250 turbo will not start without glow plugs (even in the summer it seems) I always thought it was weird why the turbo motor would depend so much more on the glow plugs for starting.

With the parallel manual glow system the entire controller can fail and several glow plugs may be out, and I still can get the truck going in an emergency.

 

dyrtbyrd. I found a picture but I don't know how to copy it. So, go to page 5 of this forum. Go down the page to the fourth thread from the bottom, called glow plug controller or relay. Go to the third post down, from Dave, and he has a link. See if that looks like yours.

 

My wiring is a bit different, NO white wire-where I need to bypass, also that is where the other yellow wire is. Other differences-small, Are all controller wiring colors the same or do they vary by motor size? Year of vehicle? Guess I might need more help on installing my bypass switch.

 

It goes by years. Only two that I know of, but I am no expert. Earlier like before maybe 87 and after 87 or 88, I'm not sure the exact change year. But you should have the newer one like mine.

 

i did the same thing then was able to find the bad ground & now have both wires connected kinda nice to know that if i get a bad ground agian just push the button.

 

trike,
So your controller setup is the same-wire colors-as the pix you suggested I look at? Now I think on pg 6 top of the page, the pix posted by dave? Cant find white wire to do my bypass so guess Ill keep plugging in til I get the $170+ for the new unit. Really dont want to burn my gp's or worse guessing which wire to bypass.
Thank though,
By

 

I think the older style can be found at www.members.shaw.ca/k2pilot/

 

Look at the picture.
On the relay you have two big terminals and two small terminals.

The big terminals are for battery power in(always hot) and glow plugs out(hot when the relay is closed) via the metal strip.

The two small terminals, one has two red wires on it. One goes to the controller below the relay and the other goes to the ignition switch. It should have battery power on it when the key is turned to ON.

The other small terminal has one wire on it, this is what should be the white wire. The white wire goes into the controller. This is the terminal that needs to go to ground to close the relay.

A common problem with the new style controller is the black ground wire connection corrodes and is not making good contact, check that first.

The glow plug system on the shaw site is the old pre 87 system. Yours is nothing like that and that drawing will not work on yours.

Controller wire colors are green, yellow, red, black, blue, and white. You should have all those colors and number of wires entering the controller.

 

Dave,
So I found where my white wire goes-little off white looks yellow guess from the heat?
From what I'm reading after disconnecting that white wire I ground it? And I connect that ground to the momentary switch and the other side of the switch to a hot wire? OR tape that off white wire after disconnecting, connect a wire from that relay post to where the white wire was to the Momentary switch and run a ground at the other end of the momentary switch?
Sorry but this is all confusing to me and I want to do this right Thanks!!!