Manual glow plug wiring help?

[nitroguy]

Looking to wire up my engine, and I've got two hacked together home made systems. Oh my.

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So, I know the right answer is to buy Wes' system, but that cash won't be here for a bit longer. So, in the meantime, I want to hook up my own.

I'm assuming the big two orange wires on the engine side (top one in photo) need to be connected to the big two black with orange tracer on the chassis side (bottom of photo, headed to the left). Any idea what the other wires might be on the right? On the left?

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Any help or diagrams or identifying marks are super helpful at this point. Any wire I can pin down and eliminate from the maze is a good one.

Thanks all!

 

[IDIBRONCO]

Which truck is this on? Do you happen to have the engine side of the wiring harness that will match the truck side? If so, I'd use that one. I know that the smaller, white colored connector appears to be from a 6.9.

 

[nitroguy]

Good question. This is the 89 with the 7.3.

The original harness that came in it is toast. Glow plug connectors literally crumbled in my hands, and wires that were cut and loomed in, dead ending.

Best I can tell, I'm trying to combine a 6.9 and a 7.3 harness.

 

[IDIBRONCO]

That's what I thought and looking at your Smokey Pete pictures after seeing this confirmed it. The glow plug connectors themselves probably didn't crumble, it was just the insulation over the metal connectors. You can replace the connectors on the 7.3 wiring harness. Do you still have the 7.3 harness? If not, maybe you could find one in a junk yard somewhere or maybe someone on here might have one. There are some here who could tell you how to wire up a new harness of your own, but I can't even begin to tell you how it's done.

 

[Randy Bush]

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This should help you.

 

[franklin2]

See if that white/red stripe wire goes back to the oil pressure sending unit (switch in the case of a 7.3). If you have a red with white stripe wire, that should go to the temperature sending unit for the block.

 

[Va_Mike]

I think I have a spare 7.3 engine side harness if your in need of one.

 

[nitroguy]

Thanks for all the help guys!

And thanks for the offer VA Mike! I might take you up on that if this one doesn't work out.

I got it all together, wired most everything up and my fss and high idle all work.

But I'm having issues with the glow plug relay. First off, the old one was dead (not surprising considering the number of shorts in the system). So I'm working on creating my own bypass unit.

Plan is to omit the glow plug timer altogether, and just use a push button. I've got hot coming in to one big terminal, and connectors to the engine glow plug harness on the other. But if I don't use the glow plug controller, do I still switch ground like most 7.3's? Or would I switch 12v+?

In short - what do I run to the small posts of the relay? I can't seem to figure out how they work.

 

[Runningaford]

Thanks for all the help guys!

And thanks for the offer VA Mike! I might take you up on that if this one doesn't work out.

I got it all together, wired most everything up and my fss and high idle all work.

But I'm having issues with the glow plug relay. First off, the old one was dead (not surprising considering the number of shorts in the system). So I'm working on creating my own bypass unit.

Plan is to omit the glow plug timer altogether, and just use a push button. I've got hot coming in to one big terminal, and connectors to the engine glow plug harness on the other. But if I don't use the glow plug controller, do I still switch ground like most 7.3's? Or would I switch 12v+?

In short - what do I run to the small posts of the relay? I can't seem to figure out how they work.

Disclosure, it's been a while since I've messed with my glow plugs.... However you wire it, just remember to complete the circuit; it's always a loop, and a switch is simply a break in that loop(whether +, or -); if that helps at all.

 

[snicklas]

I think if I were wiring from scratch, I would switch the ground.

One, that is what IH did on the 7.3 system, it controls the ground to the relay. To do a manual bypass on a 7.3 system, you supply a switched ground to the post the white wire is on. You can even leave the white wire connected from the controller and let the controller do it’s thing, or over-ride it.

Two, If it shorts out, all it does is turn on the plugs and burn them out... not a good thing, but you won’t be creating sparks like a “hot” short would and potentially cause a fire.....

I would run a short jumper from the + hot “big post” that already has a constant battery connection, and make the long “control” wire a ground that goes into the cab.....

This is just my opinion.....

 

[nitroguy]

I think if I were wiring from scratch, I would switch the ground.

One, that is what IH did on the 7.3 system, it controls the ground to the relay. To do a manual bypass on a 7.3 system, you supply a switched ground to the post the white wire is on. You can even leave the white wire connected from the controller and let the controller do it’s thing, or over-ride it.

Two, If it shorts out, all it does is turn on the plugs and burn them out... not a good thing, but you won’t be creating sparks like a “hot” short would and potentially cause a fire.....

I would run a short jumper from the + hot “big post” that already has a constant battery connection, and make the long “control” wire a ground that goes into the cab.....

This is just my opinion.....

Very helpful. I'll go this route.

Should there be anything on the opposite "small" post? I think there were two red wires to that one.

 

[snicklas]

Very helpful. I'll go this route.

Should there be anything on the opposite "small" post? I think there were two red wires to that one.

If you are going 100% Manual (no controller) then you need:

One large post fed with a +12 Volt decent sized lead from the battery (or the starter solenoid like everything else) protected with a BIG fuse (like 200ish amps, or a fusible link). I like the pre-made starter solenoid to starter wires from the auto parts store.

The other large post goes to the glow plug harness / plugs

One small post need a +12 Volts lead. With switching the ground, you could run a short jumper from the the +12 large feed post, to one small post.

The other small post will need your switched ground wire. When you ground it, it will complete the circuit for the coil and pull the contacts closed and heat the plugs

 

[nitroguy]

Yes! This is exactly what I was looking for. Thank you.

And I wouldn't have done the fuse, so I will make sure to include a fusible link in the main +12v onto the big lug.

Thanks!!