So I put on a new glow plug relay today and my glow plug light still won't come on, so I'm guessing my glow plug controller is bad and I don't want to spend the cash for a new one, so how do I hook up a manual glow plug switch?

I have the old style glow plug system.

also is there anyway to wire it up so that my wait to start light still works when I push the button?

 

the wait to start light wont matter if you do a push button cause your bypassing the controller so it will stay on the whole time. all you have to do to make it a push button is run 12v to a switch(button) and run the power out line to one of the small threaded terminals on the solenoid. as soon as you put 12v to it you will hear it click. some say S on the plastic by the post. read this post first.... https://www.ford-trucks.com/forums/9...old-style.html

 

Ah ok...so all I have to do is fined a 12V source that turns on when the key is at half, run that wire to the switch, and from the switch to the purple wire, and when ever I push the button the wait to start light will stay on til I let go of the button?


so another question, what size wire should I use and does it matter what kind of a switch I get?

 

ive got a different glow plug system then you do, my 90 is a totally different setup then you got bud. i dont know if yours will come on or not when you run power to it. but again, the light wont matter since your controlling the glow plugs yourself. without the controller working itself then the light wont do what you want it to.

 

I know the light won't matter if it's on a manual button.....I just want the light to light up though....no real reason behind it....I just think the light would be cool.

 

you can always run the 12v to the solenoid AND to the purple wire that goes into the cab and lights up the light. easy enough eh?

 

That would work!

 

On the old style system, the wire to the dash light is the third wire (black with pink stripe) on the glow plug terminal of the relay.

So the Wait to Start light will still work.

What kind of switch, momentary switch only, that way it can not be left on or accidently bumped on burning up your glow plugs.

 

So if I put in a push button do I just unhook the controller and fill in the hole with a pipe plug or do I just leave it plugged in?.....since I would be unhooking the purple wire I guess I could leave it plugged in but I don't know.

 

I would leave the controller where it is.

More than on report of the controller twisting off when you try to remove it.

If that happens, you now have a coolant leak.

I switched mine to manual control when the original controller died.
The controller stayed there until the engine was out of the truck.

When I built my current motor, 1/2" pipe plug does a nice job of sealing the hole.

 

Alright....sounds pretty straight forward now......thanks for all your help Dave!