#2 gen light on

I wish I could do less fixing and more driving! Latest problem is the #2 gen light came on bright while driving and doesn't go out. I read on another post that it could be a fuseable link that is the cause. Now to replace that link. If it connects to the firewall near the glow plug relay do you have to replace the entire wire from the alternator? I don't see where it can come apart. I hate to sound so ignorant but I want to do these things myself if at all possible. I see the black connectors, I thought that was the fuseable link itself. If its bad is it visible or must it be tested. Thanks for the help.

just cut before the fusible link and splice in the new one.

But first please measure the voltage at the alternator. The Gen2 is the passenger side alternator, and should be putting out ~29volts with the engine running. If its not you either have a loose belt or your alternator needs to be rebuilt.

You may or may not be able to look at it and tell if it burned out. You will have to test it with a volt or ohm meter.

Concur, gotta verify the alternator is bad before digging elsewhere. I recently replaced both of mine, had them both rebuilt and they're working fine now.

I'm confused, if a fusable link is toast and it causes the #2 light to burn will the alternator still charge? I thought that the reason the light came on in the first place was because the alt was not operating. I will check voltage tomorrow.

Thanks

At any rate, they are 12V 100A alternators, and should put out about 14.4V ea. The combined, in series, voltage will be in the neighborhood of 28 Volts. So, when you have them tested, do not expect to have your repairman find 28V. If one or both of your alternators, which are internally regulated, is not working, it will register on your voltmeter in the low green area or high yellow if your batteries are in decent shape The charging and glowplug systems are a continuing educational experience for a lot of us here on this forum.. Especially the M1010 versions.

Re: RE: #2 gen light on

2deuce said:

I'm confused, if a fusable link is toast and it causes the #2 light to burn will the alternator still charge? I thought that the reason the light came on in the first place was because the alt was not operating. I will check voltage tomorrow.

Thanks

Click to expand...

No it will not charge, if your light burns out then the "sense" circuit for the alternator wont know to make the alternator put out voltage. The civilian trucks have a resistor built into the harness that will let the alternator keep charging if the light burns out, but the military thought that was a bad idea (rightly so) and didn't have the resistor put into these trucks.

Gen 2 light

I am new to the CUCV world so forgive me on my stupidity, but where would this fuse be for the Gen 2 light if all of the alts are putting out what they should?

Look at the top of this page. Click on resources. Click on Technical manuals. Find and download TM 9-2320-289-20. Best/fastest way is to right click on the TM listing and "save" to your computer. It will load faster and then you will have it saved for future use. If you have a CUCV, download all the TM's for it and save them.

In the "-20"(ends with -20) you will find a picture of the fuse box and identification of each fuse.

So if it is charging at the bottom of the green arc and after driving for a short distance goes between the green and the yellow thats bad?

Mine comes on when I coast or idle but goes off as soon as I hit the accelerator. Anyone have a common spot I should look at for this?

I have seen that when your light comes on and off as described by niferous, you will soon be in need of a rebuild.

It seems that age and lack of use, has alot to do with the failures we see like this. Once rebuilt with new components(diode trio, regulator,brush set, etc.) you should get 10-20 years of trouble free service from them, again.

If you shop around, everything inside one,can be bought for about $50(excluding field windings and armature).

If you have a good local rebuild shop, I would expect they can rebuild them for under $100. Just be sure to make it clear that it has an "Isolated Ground".