Alternator help! My Brain Hurts!!!

[BuyHiFi]

Please help my Brain Hurts!!

I have a 1986 CUCV. The other day my gen 1 light turned on and shortly after my Blower motor burned up. I was out so I decided to drive it home. The Voltmeter is solid High in the red. When i got home I measured both Alternators at the batteries One puts out 15.3 volts and the other is putting out 19 volts. I assumed the 15vlt was ok and the 19vlt was a bad regulator. I also noticed the truck was hard to start and now will not start at all and have found out that all the the glow plugs are burned up. I assume that one alternator is bad and burned up the blower motor and Glow plugs. I was forced to drive it down the street the other day to pull my other car out of the snow! What I noticed was, when I started the truck (barley) The voltmeter was in the red, but the light was out. For the heck of it I tried turning the fan on, and as soon as I did the gen1 light turned on, but the fan did not come on. I shut the fan off, the gen 1 light goes back out. Then When I put the truck in 4wd the 4wd light turned on and also the Gen 1 light again. I put it in 2wd the light turns back off and so on! Crazy!

I assume that I will replace the bad alternator. I also ordered a blower motor and glow plugs. These are my issues. 1. I need to install the glow plugs to check the alternator again but am afraid I will burn them up again. 2. Why are the 4wd and the blower motor turning on the Gen 1 light?

I really need some help! I would appreciate it!

Todd Claxton
240-793-7356
todd@lovevoodoo.com

 

[BuyHiFi]

Any suggestions? I could really use some help

 

[Ken_86gt]

If you run that truck while it is putting out 19V you will burn everything out- that is why your voltmeter is in the red. If you haven't already you will also burn out the lights and ruin the battery...I have seen batteries explode from overcharging. What help do you need? you know that your alternator needs work and you continue to drive it it? Don't troubleshoot anything else until you fix the cause of all of your problems.

 

[BuyHiFi]

I had no choice, my wife was stuck in the snow blocking the road. I know I need to replace the alternator. The question is why does the gen 1 light come on with the fan switch and when I put it in 4wd?

I also measure 25vlts at the glow plug. I that correct?

 

[Warthog]

The Gen1 alternator (drivers side) is 12 volts, it supplies 12 volts to the front battery and the 12v electrical system.

The Gen2 alternator (pass side) is also 12v and takes 12 volts from the Gen1 (connects to the "ground" terminal) and adds 12v to output 24v for both batteries, glowplugs and starter systems only. The rest of the truck is 12v.

Both of these alternators have isolated grounds (so the 24v will work and no fireworks) and can be rebuilt by almost any starter/alternator shop. You can not buy them from your local parts store. You have to tell them isolated ground. If they don't understand that then run....

Both alternators should put out 14v for a total of 28v.

To answer your questions.....

Glow plugs - The system is designed (flawed in some peoples opinions) to take 24v, run it thru the BIG resistor pack behind the air cleaner, use the resistance of the plugs and supply 12v to the 8 plugs. If one plug burns out then the resistance decreases and the voltage increases to the others and they start burning out also. In the end the last one is getting the full 24v and dies a very painfull death. You can modify the system so the you bypass the resistor pack and only supply 12v to the plugs. No wire cutting involved.

Gen1 light - All the electrical systems are 12v (except starter, glowplugs) and run off Gen1. If Gen1 (driverside) is bad or marginal, anytime you put a load on it the Gen1 light is designed to come on.

The first thing you should do is read the WiKi page Cucv - Steel Soldiers::Military Vehicles Supersite
download the Tech Manuals, Read the trouble shooting sections of the -20 and go from there.

I would pull the batteries and pull the alternators and have all them checked at any of the local parts houses. They can check them but not sell you the correct new ones. Make sure you lable all wires for reinstallation.

When you checked the voltage at the batteries, which was 15 volts and which was 19v? You should have had 14v at the front battery and 28v at the positive terminal on the rear battery (this assumes you use the chassis as the ground) if both alternators are working correctly

Hope this helps.

Warthog

 

[BuyHiFi]

Thank you very much. I replaced teh glow plugs 6 months ago however one was stuck and I didnt want it to break off so I left it. I replaceed the others. Maybe that is why the burned up again

 

[Warthog]

Thank you very much. I replaced teh glow plugs 6 months ago however one was stuck and I didnt want it to break off so I left it. I replaceed the others. Maybe that is why the burned up again

Yeap that will do it. They where getting more that 12v and they started failing as a group.

Do a search on removing broken glowplugs. Many people have written about how to remove them. If the tip breaksoff you have to remove the injector and use forceps to retrieve the tip.

Let us know how the alternators and batteries test out. Autozone (most local compaies) will check them for free. They will also charge your batteries....