Both GEN 1 and GEN 2 Lights Not On at Start

[Bravo2Uniform]

I recently lost all power to my 1986 M1028. A wire from the engine wiring harness block had rubbed the fire wall and shorted out and no power was going to the harness.

I repaired that and now I can get the truck to turn over but neither the GEN 1 or GEN 2 lights activate when I try to start. The Oil Pressure light does illuminate. From reading the FAQ, I found that , "The Heater fuse supplies power to both the heater circuit and PIN#5 of the instrument cluster. PIN #5 supplies power to the GEN1 bulb, the 4x4 Indicator Lamp and the Oil Pressure circuit." I'm confident then that current is at least making it to the instrument panel since the oil pressure lamp is lit.

I verified that the bulbs in the GEN 1 and GEN 2 are good, that the light sockets were contacting the copper film, and all the fuses are good. FYI - the wait light and water in fuel are functioning correctly as well.

What is the commonality of these two lights? I mean other than the fact they are trying my patience.

 

[Curtisje]

Can you start the truck? If so are the alternators working?

Your short may have fried your alternators. Your lights may be working properly.

 

[Bravo2Uniform]

Can you start the truck? If so are the alternators working?

Your short may have fried your alternators. Your lights may be working properly.

Thanks for the reply.

The truck won't start. I'm slowly working through the troubleshooting procedures.

I can tell you that my glow plugs are cycling on and back off rapidly. From my reading I have learned that may be caused by too high voltage and the GP controller is shutting the glow plugs off. I have verified the 0.28 ohms on the ballast resistors.

As the tree said to the lumberjack, I'm stumped.

 

[Curtisje]

I think you may have to pull your alts and get them checked. I had a 24v short to the frame fry both my alts a while back. Good luck.

 

[Bravo2Uniform]

I think you may have to pull your alts and get them checked. I had a 24v short to the frame fry both my alts a while back. Good luck.

Thanks for replying.

I think are right - at a minimum I could eliminate that as a problem.

 

[MarcusOReallyus]

I think you may have to pull your alts and get them checked. I had a 24v short to the frame fry both my alts a while back. Good luck.

There's a sticky at the top of the forum that describes how to test them on the vhicle.


You may have fried one of your fusible links.

 

[Bravo2Uniform]

There's a sticky at the top of the forum that describes how to test them on the vhicle.


You may have fried one of your fusible links.

Thank you. Those "stickies" are invaluable reading. I will put that test on my enormous stack of troubleshooting procedures.

This is no different than finding out why my wife is angry. Takes a long time, I'm never right the first 400 times I ask what's wrong, have to keep trying ...

It's wildly inappropriate to make an owner's manual joke here.

 

[MarcusOReallyus]

It wildly inappropriate to make an owner's manual joke here.

Also not safe. Your wife might read it.

Come to think of it, you are probably in trouble already.....

 

[Bravo2Uniform]

Also not safe. Your wife might read it.

Come to think of it, you are probably in trouble already.....

I'm married = in trouble already.

Let me give you some wisdom from restoring my M38A1 - NEVER, and I mean NEVER, utilize a time when your wife is mad at you to test drive a vehicle you are restoring / working on. Why? Because you don't want to here her laugh and slam the phone down when you call from 15 miles away asking her to come pick you up.