At a Complete Loss: Can’t Get GP Relay to Click On

[Fullthrottle78]

I just don’t know what to do anymore on my 82’ 6.2.…

This all started by me screwing up the GP system by energizing the pink side with the Power Probe while both the pink and blue wires were connected.
Before that screw up, the GP system worked fine by turning the key. I think I fried the controller, so I was going to install a manual GP button in the cab.

I used to be able to get the glow plug relay(solenoid) to audibly Click On by using the power probe… energizing the pink wire side with the PP grounded to the blue side..
Or getting it to click on by hitting the - button on the while probing the blue side while both pink and blue are attached…
Now I’ve got nothing!
I just installed a Ford relay(solenoid) and still nothing. I’m at a complete loss. Just when I was starting to figure this out the relay(solenoid) stopped clicking on with the PP.

Please for the love of the rest of my sanity… help

[More Power]

The 1982-84 glow plug systems were always the most finicky, hardest to troubleshoot and most expensive to replace.

I recommend upgrading to the 1985-93 glow plug system. The modules are less expensive and are much more reliable. We did a conversion article some time ago. It's not that difficult.

Manual glow systems can be made to work. But, that solution gets complicated whenever someone else drives the truck. My philosophy was always to make my vehicles drive-able by anyone with as little instruction as possible - easier for you, easier for them and less likely to damage the truck's systems.

[Fullthrottle78]

Thank you for your reply. Yes, upgrading the controller to the newer version is something I thought about.
However I do want a manual glow plug system as I'm not worried about other people driving my truck.
Wouldn't installing a momentary switch for a manual glow plug system negate the glow plug controller altogether?

[DmaxMaverick]

Welcome aboard!

Installing a momentary switch and relay manual system, parallel to the OEM GP control systems (old or new), is just fine. Both are relay protected, so the only "feedback" would be the GP/WTS lamp illuminating.

[Fullthrottle78]

Thank you I appreciate it. So I think my GP controller is fried. Would installing the ford type relay and momentary switch still work? If so do you have instructions on installation?

[DmaxMaverick]

You just described the procedure, but I'll expand on it.

Mount the Ford starter relay to the inner fender near the #7 cylinder. Where exactly is not important, as long as it's grounded, close to the original controller (old or new, so the GP leads will reach), and doesn't interfere with anything else. The momentary switch should be mounted where you can reach it while seated for starting/driving. I mounted mine below the instrument panel on the left side, where it can be easily reached while seated, or standing on the ground outside. It can be supplied with 12V from any source capable of 10A or more (like the cigar lighter circuit). The momentary output power goes to the "S" or small pole on the new relay. The Batt+ large lead from the old relay, and the GP leads connect to the large new relay leads opposites, similar to how they were previously connected. Make sure the GP lead harnesses are clear of any interference and excessive heat. That's it.

[Robyn]

One thing to be careful of

The glow plugs should be changed to 60G plugs
The earlier plugs (Unless they have been changed) were much faster heat time and if left on too long can/will swell and burn out.

The 60G plugs are much better....A 10 second or so on time will usually lite the fire..

The original system "Pulsed" the plugs after startup to help keep the engine running smooth and minimize smoke until the cylinders have warmed up a bit...

If after startup on a cold morning you can press your button on/off for a couple seconds each time if the engine starts to run rough.....Most times things will be fine and the initial glow will suffice to get things going.......

I agree with Maverick on the relay setup.......I have done a few of these over the years....The Ford relay works well.

[Fullthrottle78]

Thanks for your reply… I tried this and I have nothing. I’m really at a loss here.

[Fullthrottle78]

Do you have a link to that conversion article? I cannot get a momentary switch button to work.

[Fullthrottle78]

is the ford relay different than this one?

https://www.amazon.com/dp/B000O3ICDA...roduct_details

One thing to be careful of

The glow plugs should be changed to 60G plugs
The earlier plugs (Unless they have been changed) were much faster heat time and if left on too long can/will swell and burn out.

The 60G plugs are much better....A 10 second or so on time will usually lite the fire..

The original system "Pulsed" the plugs after startup to help keep the engine running smooth and minimize smoke until the cylinders have warmed up a bit...

If after startup on a cold morning you can press your button on/off for a couple seconds each time if the engine starts to run rough.....Most times things will be fine and the initial glow will suffice to get things going.......

I agree with Maverick on the relay setup.......I have done a few of these over the years....The Ford relay works well.

[DmaxMaverick]

That "looks" like a Ford starter relay model, regardless of how it's labeled or marketed. It doesn't show the rating, but I'd suspect it's no different and fully capable. Any number of them are acceptable, and they all do the same job. Don't spend an extra $10 just for a "Glow Plug Relay" label. It's function is simple, and it only has to work.

If you can't get the GP's to light off, check for voltage where it's supposed to be. One side of your momentary switch must have Batt+, while the other side should be open (at the time you expect it to work, before closing the contact), and connect to the S pole (or spade tab) of the relay (if the relay has a 4th pole, it's for older vehicle ign. systems, so not necessary for GP use). Depending on where you source the momentary switch power, it may or may not be Ign. switch dependent. There are 2 large lugs on the relay. One is for Batt+ (constant) power, and the other goes to the GP harness. If you don't have Batt+ voltage where it's supposed to be, that needs to be addressed before anything else will work. The large Batt+ wire to the GP relay will/should have a fusible link between the relay and battery source. If it has no power chase it back to the source. A fat, molded piece along the wire will be the fusible link. Whey they fry, they will almost always burn the insulation, making it very brittle.

[Fullthrottle78]

So I got it to work. The relay needed to be grounded off the ‘S’ terminal and 12v sent to the ‘I’ terminal.

[DmaxMaverick]

That's backwards. The I pole is for Ignition coil power, in its originally intended use (as a Ford, et al, starter relay). The momentary Batt+ should go to the S pole. If it doesn't work this way, something is amiss (like it's running power backward through a diode, which will eventually fail, and short circuit). If the relay itself is grounded, it should not need a separate ground. It should ground through the mounting hardware. If it's isolated by some means, then it needs a ground supplied to the mount. The ground is only for the exciter circuit (excites the solenoid coil, powered by your momentary switch), and has NO association to the large poles that complete the GP circuit.