Bypass the glow plug contoller
- Thread starter Trex
- Start date
You only need one wire to the controller. All you need to do to bypass it is provide a ground to the relay. Should be that white one with the tag on it if I'm not mistaken. Take that off and run your wire from there to your switch, then the other terminal on your switch to ground.
7.3L IDI Manual Glow Plug Controller/Switch Wiring
Information regarding the installation of a manual glow plug control switch on the 7.3L IDI diesel found in 1988 to 1994 Ford pickups. Topics include how to install and wire a manual glow plug switch in addition to information on how it works.
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Big Bart
Tow&Slow
1) What he said.
2) Be sure to clean up the terminal with the yellow wires that is rusty/corroded. Those are the fusible link wires that bring power from the battery to the controller.
3) If your toggle switch is not momentary (Won’t stay on with out holding it, toss it and get a momentary one.) Many bad endings for members who said they would not leave it on. (Sometimes it’s others who bump it on and it gets left on.)
2) Be sure to clean up the terminal with the yellow wires that is rusty/corroded. Those are the fusible link wires that bring power from the battery to the controller.
3) If your toggle switch is not momentary (Won’t stay on with out holding it, toss it and get a momentary one.) Many bad endings for members who said they would not leave it on. (Sometimes it’s others who bump it on and it gets left on.)
OK fellow's, I hooked up my wire from switch to controller where i took the white wire off and grounded the other wire from switch to ground, no go, will not work. Do i need to cut the wait to start blue wire and put it on with my other wire from the switch on the controller or should this all work leaving the blue wire as it is?
Big Bart
Tow&Slow
TRex,
Don’t mean to be captain obvious but the key was in the on position when you tested correct?
So the top part of the controller is basically a starter solenoid. So if the small post with red wires has +12v with the key on, and you supply ground to small post with the white wires it should click and connect the two large posts Together sending power to the glow plugs.
1) Confirm you have +12v power to the small post with the red wires when the key is on.
2) That you are supplying a good ground to the small post with the white wire.(Test light to confirm.) When you do add ground you hear it click the solenoid on. If it is not working, replace it. Probably why your glow plugs where not working in the first place.
3) The big post with the two yellow wires has +12v all the time. If not you need to fix that.
4) When you add ground to the small post with the white wire, that you now have +12v on the other big post with the metal tab. Also that you have power now at both banks of glow plugs.
Let us know what you find out.
Don’t mean to be captain obvious but the key was in the on position when you tested correct?
So the top part of the controller is basically a starter solenoid. So if the small post with red wires has +12v with the key on, and you supply ground to small post with the white wires it should click and connect the two large posts Together sending power to the glow plugs.
1) Confirm you have +12v power to the small post with the red wires when the key is on.
2) That you are supplying a good ground to the small post with the white wire.(Test light to confirm.) When you do add ground you hear it click the solenoid on. If it is not working, replace it. Probably why your glow plugs where not working in the first place.
3) The big post with the two yellow wires has +12v all the time. If not you need to fix that.
4) When you add ground to the small post with the white wire, that you now have +12v on the other big post with the metal tab. Also that you have power now at both banks of glow plugs.
Let us know what you find out.
OK, Had some time to play with it today, Seem's the controller is bad cause i have 12 volt on the white wire and 12 volt on the others but when i cannot get 12 volt on the busbar side going to the glowplugs when the key is on the run position. So i am assume the controller is bad. This is on a 1992 7.3, what part # controller and where to get it from, also what kind of price to expect?
It might just be the relay then if that's the case. You can replace that without replacing the controller, much cheaper that way.
The relay is the round black thing mounted in the center of the square black thing in the picture below. It should go thunk when you activate it.
Think of this just like a starter relay on the fender. It does the same job, except instead of sending big power to the starter, it sends big power to the glowplugs.
Think of this just like a starter relay on the fender. It does the same job, except instead of sending big power to the starter, it sends big power to the glowplugs.
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glow plug controller by D Franklin, on Flickr
Big Bart
Tow&Slow
Try the following.
1) Turn the key to on, you should have +12v on the small post with the red wire on the GP controller.
2) Use a jumper wire from the negative post on your battery to the the small post with the white wire. The solenoid should now click. If it clicks it is now connecting the two large posts together. If it does not click replace it.
3) Some reasons your controller might not be working -
a) You have 3 or more glow plugs that are bad. (So the controller is not turning on the glow plugs.)
b) One or both of your glow plug wiring harnesses is bad. (So the GP controller is not turning on The glow plugs.)
c) Your controller ground wire black or brown wire (Can’t tell from the pic.) is not making a good ground. Thus no ground can be made via the white wire to activate the relay.
d) The controller or the relay on top of it, is not working and needs to be replaced.
I hope that helps.
Pro tip, you're going to have 12 volts on the white wire unless the controller is grounding that wire..
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