Gen 1 light and electrical issues

[QuietProfessional]

I’m starting to get into an m1008 I bought. Only the gen 1 light would turn on and then dim once it was running. The batteries weren’t being charged by the alternators and if I turned the lights on the batteries would be drained quickly. I replaced all bulbs on exterior and interior. Gen 2 had no bulb or receptacle. I followed instructions from a previous thread and did 168 bulb for gen 1 and 194 bulb for gen 2. Gen 2 still doesn’t come on at all. When all the bulbs were replaced, I turned on the lights, everything turned on but then the headlights went out after a couple seconds and won’t turn back on. I’ll clean the contacts and check the gen 1&2 bulb’s board for continuity once I have time to get back to it. I’m hoping it’s something simple like that and not a short I have to dig for. Another thing worth noting is the truck will start without the service lights switch in the run position. Does anyone have any experience with something like this that can offer a best guess?

 

[MarcusOReallyus]

Welcome, QP!

Have you downloaded the TMs? There is a detailed troubleshooting section that was designed for 18 year olds who know nothing. Very helpful. and FREE!

Also, there is a sticky at the top of the forum entitled, "Testing the alternators on the vesicle." There might be some helpful info there. Also see the "Helpful threads", sticky, again, top of the forum. Tons of good info. You'll particularly want to check out the stuff on fusible links.

Speaking of which, have you checked those? It's not always obvious when they are blown.

Lastly, any chance your truck was converted to 12v? It makes a huge difference in troubleshooting!

 

[QuietProfessional]

Welcome, QP!

Have you downloaded the TMs? There is a detailed troubleshooting section that was designed for 18 year olds who know nothing. Very helpful. and FREE!

Also, there is a sticky at the top of the forum entitled, "Testing the alternators on the vesicle." There might be some helpful info there. Also see the "Helpful threads", sticky, again, top of the forum. Tons of good info. You'll particularly want to check out the stuff on fusible links.

Speaking of which, have you checked those? It's not always obvious when they are blown.

Lastly, any chance your truck was converted to 12v? It makes a huge difference in troubleshooting!

Welcome, QP!

Have you downloaded the TMs? There is a detailed troubleshooting section that was designed for 18 year olds who know nothing. Very helpful. and FREE!

Also, there is a sticky at the top of the forum entitled, "Testing the alternators on the vesicle." There might be some helpful info there. Also see the "Helpful threads", sticky, again, top of the forum. Tons of good info. You'll particularly want to check out the stuff on fusible links.

Speaking of which, have you checked those? It's not always obvious when they are blown.

Lastly, any chance your truck was converted to 12v? It makes a huge difference in troubleshooting!

Hey Marcus,
Thanks for the quick response and welcome. The fuses are good. There is a wire running into the ignition portion of the panel. Is that indicative of a 12v system?
I located the TMs I’m started to dig into them now.

 

[MarcusOReallyus]

Is that indicative of a 12v system?

Nope. Except for the starter circuit and the glow plug circuit, the truck is 12v. So there is lots of 12v stuff in there. Best way to tell is to take a look at your batteries. Are they wired in series or parallel? If you aren't sure, see here.

Check that and let us know, and we'll go from there.

It wouldn't hurt to post some pictures of your wiring in the engine compartment. We can make some educated guesses from that.