Glow Plug Relay issues....I know, I know

[noel.isaac]

Hey guys. I have a m1009 and a 1028. I have been troubleshooting the glow plug issue on my 1028, and have come to the conclusion that I will be disconnecting the blue wire at the relay, and hooking up the relay to a momentary contact switch (Push button).

In several of the previous threads, I have read that i need to ground the terminal of the blue wire through the switch. When I do this, I get nothing....but when I hook the terminal up to a hot wire, it actuates. That is how I thought a relay worked anyway. The relay that is on it is a 12v continuos relay that looks like an old Ford starter solenoid, and the orange wire is on the glow plug side.

is this an idiosyncratic event, or are the previous threads wrong?

Thanks guys, Noel

 

[Crash_AF]

The previous threads are not wrong. If your relay works as you describe, it is the wrong one.

The 12V is provided by the pink/black wire and the light blue wire is the ground. There are two types of relays like the GPR in these trucks. One is a base grounded unit, it is grounded through the mounting base and the two terminals are both 12V, one is an activation terminal and the other is an ignition terminal that provides 12V to circuits that need 12V while starting. The Ford starter solenoid is this type, as it provides a full 12V to the coil while cranking for a hotter spark.

The other type is an isolated ground type like our GPRs, the two terminals are 12V signal and ground. The ground is the switched part of the circuit instead of the power being switched.

A base grounded unit WILL NOT WORK with our stock glow plug system because the ground is not controlled. Since you have a 1009 that I presume works correctly, take the GPR off of it and put it on the 1028. See if that solves your problem. If it does, you need to purchase the correct relay.

Later,
Joe

 

[noel.isaac]

Thanks, I will do. My 1009 has the stock flat mount type relay, which I know is impossible to duplicate. Do you happen to have the correct relay make and part # and I will go ahead an order one?

Thanks again.

 

[noel.isaac]

FYI, I am darn near ready to drill out my intake manifold and install a intake preheater off my old deuce. I'm sick of working on this and it is getting cold out!

 

[Crash_AF]

You can use either

NAPA - ST85
Or
Ford Powerstroke relay
NAPA - ECHGPR110

You can also cross those numbers at any other parts house and get one cheaper if you don't like NAPA's pricing. The Ford relay looks different, but works the same.

Later,
Joe

 

[ida34]

Did you have the key in the on position when you grounded the blue terminal? If you did not then you did not have positive to the relay and it should not have worked. IIRC when the ignition switch is off it will actuate when you apply power to the blue wire. I don't think anything is wrong with your relay but you can bench check it. Apply 12 volts to the small terminals and then check for continuity at the large posts. Also check continuity between all the terminals and the metal casing. There should be none there.

The main thing is the key has to be on for the relay to work then the blue wire is grounded.

 

[noel.isaac]

The previous threads are not wrong. If your relay works as you describe, it is the wrong one.

The 12V is provided by the pink/black wire and the light blue wire is the ground. There are two types of relays like the GPR in these trucks. One is a base grounded unit, it is grounded through the mounting base and the two terminals are both 12V, one is an activation terminal and the other is an ignition terminal that provides 12V to circuits that need 12V while starting. The Ford starter solenoid is this type, as it provides a full 12V to the coil while cranking for a hotter spark.

The other type is an isolated ground type like our GPRs, the two terminals are 12V signal and ground. The ground is the switched part of the circuit instead of the power being switched.

A base grounded unit WILL NOT WORK with our stock glow plug system because the ground is not controlled. Since you have a 1009 that I presume works correctly, take the GPR off of it and put it on the 1028. See if that solves your problem. If it does, you need to purchase the correct relay.

Later,
Joe

Okay, I replaced the relay with the Borg Warner S-55 today, and I followed the directions to a tee. Same thing. Out of curiosity, I checked voltage between the blue wire and the incoming 24v resisted wire and got nothing. I then checked the voltage between the Pnk wire and the 24v resisted wire and got 24 volts....is it normal that the pink wire, which is supposed to provide 12 volts to the terminal, would act as a ground? it doesnt seem right to me. I then put a lead wire from the resisted wire terminal to wear the blue wire attaches, and the relay closes, which is what it was doing with the start of this thread. I pulled out hte TM and am going to check and see if the wires are wired right, but it seems that the blue and the pink may be reversed at the other end? I have no clue. very discouraging, and it looks like I may be simply unhookingthe blue wire after all and running a push button actuated relay with a hot wire....any ideas?

 

[4bogginchevys]

you can eliminate the possiblity of 24v ruining the remaining glow plugs if one goes out and make it easier to trouble shoot electrical problems in this system by feeding power to the relay from the + side of batt 1 or running a jumper from the small juntion on the fire wall to the relay. If you leave the suppressor thingy on the fire wall then you can always easily reverse what you did if you sell the truck to another enthusiast. When my GP controller card went bad I didn't have to unhook anything, I just ran a wire from the correct post of relay into the cab to my push button, then to the ground previously mentioned above the e-brake pedal. This way if I happen across a gp card I can remove the switch and the system works like normal, (would anyway if I didn't push the button). Good luck

 

[noel.isaac]

Still need help....why doES the relay engage when the blue wire and terminal are jumped to a positive? this is on a new s55 relay? if someone could explain step by step what is suppose to happen at the relay and what is going on in the pink and blue wires through out the cycle I could probably figure out my issue, which, we all can conclude, is the Module.... thanks guys. Noel

 

[woodyNla]

Still need help....why doES the relay engage when the blue wire and terminal are jumped to a positive? this is on a new s55 relay? if someone could explain step by step what is suppose to happen at the relay and what is going on in the pink and blue wires through out the cycle I could probably figure out my issue, which, we all can conclude, is the Module.... thanks guys. Noel

Always hot should be from the resistors. The other big wires only get hot when the relay is in the closed position. The pink should be hot when the key is on and the blue is ground. The controller card controls the ground side (light blue) of the relay from what I understand.

 

[4bogginchevys]

You might try a GPR 109 from napa, same as recomended relays but only about 25-30 $, I noticed yours (s55) is not listed in the fac, and has not been recomended. Good luck

 

[ida34]

I say again, are you doing this with the key on or off?

For some reason, I have found that when the key is off you get power to the blue wire and if you ground the other terminal the relays closes. When the key is on the power goes away on the blue wire and the other terminal gets power thus allowing the relay to trip when the blue wire is grounded.

You really need to break open the trouble shooting portion of the -20 electrical section and check everything systematically by the tm.

 

[doghead]

With the key off, you will measure voltage on both the pink and the blue wire. They are the ends of an electromagnetic coil.

When the controller card switches the blue wire to ground(calls for glow plug function), the circuit is completed(power to a component, through the component,and to ground)


If your controller card is not functioning, you will still measure voltage on both small terminals(because there is no completed circuit).



In the Tm(-20), there is a complete diagnostics procedure for everything other than the controller card. I would start there. You don't need to understand anything, the way it is written, just follow it step by step, and you can diagnose the components, and find your problem.

Schematics are in the back of the -20 tm.

whatever relay you chose, it needs to have the 2 small terminals "isolated" from ground(the mount), because the ground is what is controlled(triggered to function).