Gen 1 Light Staying on Alt Help Plz

[mijon]

Previous history,
- Gen light 1 would come on very lightly when my m1008 was running. And my gen #2 light would blink when I would turn on the turn signals after running for awhile. Earlier today when I was plowing out the 18 inches of snow we got here in mid Michigan. I heard a slight "poof" lost all power, (lights, and heater went off momentary but truck remained running.) After this, my Gen #1 light came on with a solid light. And my Gen #2 light came on a lot more frequently. My volt gage continued to get worse until it reached the "red zone" before I got home.

Question,
- Im having trouble finding a TM to help me diagnose the problem. I've read the sticky and didn't get much out of it. Can anyone help me out?
- Also if anyone has any advice it would really help me out. I'm thinking the Alternator for Gen 1 is gone. But not for sure....

Any help would be greatly appreciated...


Jon

 

[patracy]

The link to the TM's are up top of every page on the "Technical Manuals" link.

And the direct link to the CUCV TMs:
http://www.steelsoldiers.com/showthread.php?77609-TM-s-for-the-CUCV

Various other CUCV related info:
http://www.steelsoldiers.com/forumdisplay.php?114-CUCV-TMs

 

[63bravo]

generator

ok start by checking batteries and all connections, than remove both generators take them both to a good rebuilder and have him bench test them. also check all fuses . let ne know how you make out ..

 

[mijon]

Update: threw another alternator I had off my M1009 on the rig for the Gen 1alternator. And the Gen 1 light is still coming on. I keep loosing power after awhile because it drains the battery. Any suggestions? I know the alternator I put on works properly. What could the problem be now? Any advice would be greatly appreciated. Thanks guys. Basically same problem exists.

When I heard the "poof" sound I blew the positive terminal on the alternator loose from the alternator. So much so that the terminal was loose from the alternator (almost completely off alternator). I believe what ever caused this Is the stem to what the problem is. Why might this happen? Again any advice would help me out. I rely heavily on this truck for salting. And need to get the rig back to operational form.

Thanks for the advice so far, Jon

 

[mijon]

Forgot to mention also, my upper radiator hose busted 2 days prior and the engine bay got a bath of antifreeze. I'm thinking this is the root to any shorts or electrical problems that may have caused the positive terminal to do this. I just do not know how to track it down.

 

[63bravo]

the poof sounds like a positive cable has dead shorted to ground somwhare , could have blown fusible link in the circuit , can you give me the voltage readings at the top plastic plug and the large battery wire on the back of the alternator , the feild wire should have 12 volts while running the wire in that same plug will also have 12 volts give me the readings on both alternators , also clean and check ALL hot wires make sure their not grounding ,also check that plow pump wiring , also give me the readings of both batteries one reading with the truck running and the reading with the truck off , the anti freez bath would not play a roll in your problem .

 

[mijon]

Update

63 bravo,

I checked the areas you wanted me to check.

1. When out to start the truck and the truck wouldn't turn over not enough current from the 2nd battery ( not the main, one closest to the radiator not firewall) to turn over. Truck not running: Main Battery (closest to the firewall) read 12 volts, other battery was 11.5. Truck turned on: 12.1 on the main (firewall) and 10.5 with the other battery.

2. Driver side alternator (gen 1) Truck on: the Clip Plug (with red and black wire) had 11 volts. And 2.8 volts with the large terminal on top of Alternator next to Clip Plug ( Both shown in picture).

3. Passenger side alternator (gen 2) Truck on: Clip Plug (with red and black wire) had 22.6 volts. And the large terminal on top of Alternator next to clip plug had 22.6 volts. While the other Large terminal below the Top Large Terminal had 10.6. (Shown in picture to give you a better idea of what I'm talking about.

4. I seen a fusible link on the passenger side alternator (gen 2) could that play any role in the fusible link problems.

5. Found where all the fusible links come together (shown in picture). If there is a blown fusible link is this the location where it will be blown? I seen that there are 2 blue and 2 orange/red wires that go to one terminal (right terminal). I'm assuming these fusible links are the ones that go to the alternators. So those would be the ones to change? The other 2 red wires go to the left terminal.

If you need anymore info please let me know. Thanks for all the help thus far.

 

[mijon]

Explanation of Pictures:

First Picture: Driver side Alternator Gen 1 (tested clip plug left of large terminal and that large terminal) Plug = 11 volts Terminal = 2.8 volts
Second Picture: Fusible Links
3rd Picture: Passenger side Alternator Gen 2 Top Large Terminal Had 22.6 volts, Bottom Terminal had 10.6 volts
4th picture: Fusible links to the Engine Wire Harness Block. Right side terminal is where I believe all the alternators hook up to.
5th Picture: Fusible Links
6th Picture: Fusible Links

 

[63bravo]

ok first off fully charge your batteries ,charge them over night ,,check all fusible links with your continuity tester on your volt ohm meater,or by slightly pulling on them if they feel like a rubber band its bad,check for any burnt wires,check and clean generator bulb sockets ,you can reach under the dash without removing the insturment cludter. ok and now lets go over these voltage readings,drivers side generator plastic plug,red wire when engine off shouldn be batt voltage ,approx 13 volts,but these readings m
MUST be measured when all batteries are completly charged,now for the brown wire in that plastic plug engine off there should be no voltage,engine on should tead 13v or higher,now for the main positive lug when generator is properly charging dhoulb be 14.5 volts output,,and now lets do the pass side generator, plastic plug 26 to 28 volts, now theres two main output lugs ,top lug 28 volts lower lug 13.6 to 14.3 volts ,batteriesnow 28 volts from rear battery negitive to front battery positive front battery pos to neg 3
13.6 to 14.3 all voltage values are approxroximate the could sligjhtly vary, another thing remove large square connector at firewall ih has a bolt in the middle of the plug , u must remove ts so it can be disconnected , clean and inspected termanals un hook the batteries befor you do this use a tooth or a small brass brush , but a can of contact cleaner and spray all debris after brushing also get a good flashlight and a magnifying glass look closely, there are two brown wires in that firewall harness the one for the drivers side generator is solid brown the pass side gen has a brown wire with a white tracer concentrate on these , put it all back together hook batteries up and test voltage on both sides , thsn report back with your findings ....

 

[mijon]

Update

Okay so I got a new battery and a brand new alternator from Auto Zone (DL7157) the one suggested on the wiki on this website. I cleaned all electrical connections. Connections in the rectangular box shown in the picture. And all connections in the Engine Wire harness block. I also checked all fusible links to the wire harness block and all fusible links that go to the rectangular box. Looked under the dash and the gen lights seemed to be in okay condition.

Now for the readings

1. Batteries: Truck off: 12.7 volts battery closest to the firewall and 12 volts (one that I replaced) closest to the radiator. Truck Running: Battery closest to the firewall= 13.2 and battery closest to radiator= 11.8
2. Driver Side Alternator: Clip- Red Wire=12.1 Brown/ Black wire= 12 volts. Postive Terminal was 59 for some god for saken reason. I don't know if its because of the new alternator I put on it or not.
3. Passenger side Alternator: Clip- Red Wire= 25.6 Brown/ Black Wire= 25 Top Large Terminal- 26.1 Bottom Large Terminal-11.9


I have pictures of the alternator, rectangular wire box, voltmeter readings with the truck on, and a picture of the gen 1 light on while the truck is running also. Any more information you can give me would be great. Thanks a lot for the info you've provided so far.

 

[63bravo]

ok whats this 59 reading your getting ,59 volts 59 ohms ? , next i want yoy too test for voltage at the glow plug after it been running for 5 minutes ,lets make sure your glow plugs are going off,make sure all belts are tight,did your have generator on pass side rebuilt or replaced ?

 

[nyoffroad]

ok start by checking batteries and all connections, than remove both generators take them both to a good rebuilder and have him bench test them. also check all fuses . let ne know how you make out ..

As a quick "field" on the truck test, just take a metal object like a hack saw blade and CAREFULLY touch it to the bearing on the back of the alt. If it is working you will feel a magnetic pull to the bearing, no pull=no output. This will NOT tell you if the alt is working at 100% just that is is working. BE VERY CAREFULL NOT TO TOUCH THE OUTPUT TERMINAL!!!

 

[mijon]

The 59 was in volts not ohms. I don't know how this could be. Its the new alternator from auto zone. I replaced both alternator belts and there tight. And the relay stops the glow plugs from cycling once the truck is running. Finally the passenger side alternator was rebuilt about 2 years 2000 miles ago.

 

[mijon]

Found Problem!!!

Finally found the problem,

I used a jump wire from the positive terminal on the driver side alternator (the one giving that crazy reading of 60 volts) to the battery. Seen that I had 12.45 volts to the terminal than ( truck off) previously had 0. Knew that the positive wire was the problem. I than checked the fusible links again and found that one of the blue fusible links was blown. ( Tested the 1st time in a spot that was still getting juice.) changed the fusible link and the rig is running at correct voltage again and the Gen 1 light has gone out.

I hope this thread can be helpful to someone else that runs into this problem like I did. Thanks for all the help everyone!!