Gen 2 light stays on...

[mr.travo]

I have run a search and have not found anyone with the same problems as this truck has. It was my old work M1008 truck from Ft Jackson. My buddy bought it and I have been trying to troubleshoot a couple of Gen 2 problems.

The truck starts up and runs great. After engine warms up and drops the idle the Gen 2 light remains on (even after I bump the throttle). I tested both Gen 1 and Gen 2 and am getting ~15v off Gen 1 and ~28v off Gen 2. Both bulbs work with KOEO. I have swapped out the Gen 2 relay with a "good one" (It was a spare from a good running 1031) and no change.

Also all the contacts under the hood are nice and clean. Can't find any breaks in the wiring anywhere. Both batteries load test good and are new.

Lastly the Volt Gauge is reading in the low yellow with the truck running and warmed up. I have a feeling these two problems are somehow linked. There is, however, a mystery gray wire behind the dash that I cannot figure out where it goes or what it's for.

Any input would be great and appreciated. Thanks guys!

 

[cucvrus]

gray wire is for the light in volt meter.

 

[mr.travo]

gray wire is for the light in volt meter.

Thank you however the light for the voltmeter is still attached to the wire. It's on a black one (I believe I tucked it out of the way for the picture). Would it be for a ground or something on the light?

 

[cucvrus]

Do you have a running CUCV near by? Do you have the voltage regulator plug in the correct way. Has someone replaced the plug and hooked up the wires to the wrong side. i had that already. If you have a good CUCV near by? Do some probing with a test light and some side by side comparisons. I am not an electrical genius by far. But if I apply myself I get it figured out eventually. Good Luck. If I could help more I would.

 

[cucvrus]

Thank you however the light for the voltmeter is still attached to the wire. It's on a black one (I believe I tucked it out of the way for the picture). Would it be for a ground or something on the light?

One wire goes to the center stud in the bulb socket. The black is the outer ground wire for the socket IMHO.

 

[mr.travo]

I do but am not overly excited to tear apart my good working dash, LOL! I guess I can test the volt gauge plug to see if it's reading the correct voltage, right? I just can't shake the feeling that these two problems are somehow connected. This one has had me stumped for a little over a week.

 

[mr.travo]

One wire goes to the center stud in the bulb socket. The black is the outer ground wire for the socket IMHO.

I'll run back down there now and snap another picture of the mystery wire and the volt bulb and the back of the volt gauge to give a better visual. Maybe that can jog our minds.

BRB....

 

[cucvrus]

I will step out and look at a donor vehicle in the balmy 21 degree weather.

 

[cucvrus]

The gray wire goes to the center stud of the light socket and the black wire goes to the outer ring of the socket as the ground. that would NOT effect the problem you are having. That much I do know.

 

[mr.travo]

You are correct! LMAO! Sorry- I just can't believe I overlooked the back of that bulb.

Sorry about that. I did find yet another overlooked relay (looks just like the gen 2 relay) next to the E brake and fuse box. Any ideas what this operates?

 

[mr.travo]

Nevermind- I found out that it's the horn relay. Thanks to Warthog for posting this up. Just happened to stumble across it in another topic. http://www.steelsoldiers.com/showthread.php?50551-CUCV-Switches-Diodes-Relays

Now, still have to figure out this darn Gen 2 light....

 

[doghead]

Measure the rear battery voltage with and without it running.

 

[mr.travo]

Measure the rear battery voltage with and without it running.

I have and both batteries were in the 12's off and in the mid 13's running (if I remember correctly the running value). I will double check those numbers again tomorrow.

 

[Evil Dr. Porkchop]

5 or so years ago when I had a bad alternator in my m1009 a friend of mine gave me a replacement that he took out of his pickup. It was working fine, the reason he took it out was the Gen2 light in the truck would never go out. He changed it for another one which fixed the problem. I replaced the non functioning Gen2 in my truck with that alternator and everything worked fine, except the gen2 light was always on. Other than that I never had a problem with it, it charged the batteries just fine until I eventually sold the truck.

 

[cucvrus]

Did you look at the voltage regulator plugs to the alternators? Have they been changed? Like I said. I have seen the wires reversed because the replacement plug has the red wire in the opposite position. Happened to me once. i just kept using the test light and checked everything I could and compared it to a perfect running CUCV. I found it after and hour of 2 of checking. It was code H for chaging problems and the unit turned the truck in. CSMS just went along with the order and DRMOed the truck. Those were the days. zero expenditure and they scrapped them because of a bad starter or dead batteries.

 

[mr.travo]

Did you look at the voltage regulator plugs to the alternators? Have they been changed? Like I said. I have seen the wires reversed because the replacement plug has the red wire in the opposite position. Happened to me once. i just kept using the test light and checked everything I could and compared it to a perfect running CUCV. I found it after and hour of 2 of checking. It was code H for chaging problems and the unit turned the truck in. CSMS just went along with the order and DRMOed the truck. Those were the days. zero expenditure and they scrapped them because of a bad starter or dead batteries.

You are talking about the plastic plugs that snap into the generators, correct? If so, then yes and other than old age, I couldn't see anything wrong with them. If they are not working then the generator wouldn't be putting out, right? Just trying to get my head wrapped around this issue too.

 

[epitts]

I had this problem with my M1009,the gen was on but dim battery's charging. I changed the plug at the alt with a new one and fix several problems. YMMV