Gen 1 Light - Overcharging

[donalloy1]

Gen 1 light bright Red when driving? Volt meter in overcharge range. Time to get happy with TM's. Any hints from those that have been there before me. Will dive into to TM's and see if I can figure why she is not regulating properly? She brought me and son home safely. Its all good. Hopefully did not cook batts? DMLII sends.

 

[donalloy1]

According to TM I need a new Alternator. So much for cheap fix. Will look closer in morning with sunlight on my side.

 

[Ken_86gt]

You could probably just rebuild it yourself, you would save some money. You need parts for a 27si alternator or you can try these links:
http://www.steelsoldiers.com/cucv/59583-more-cucv-alternator-questions.html
CUCV Complete Alternator Rebuild Kit - CUCV Electric

 

[Dr.Jay]

You could probably just rebuild it yourself, you would save some money. You need parts for a 27si alternator or you can try these links:
http://www.steelsoldiers.com/cucv/59583-more-cucv-alternator-questions.html
CUCV Complete Alternator Rebuild Kit - CUCV Electric

Great links, Thank You!!

Also the main internal alternator components (not including the ground isolator washers, and stud) are the same as those used on a 1978 Cadillac Sedan Deville with multi port fuel injection.

 

[donalloy1]

Found below troubleshooting guide last night and went to town this morning. All checks out good after correcting poor contact on positive terminal for battery nearest firewall. Always start with the easy stuff. Gen 1 light still pulsates dimly but not a steady bright red when in throttle. Going to replace crappy positive battery terminal and see what happens? My instinct tells me that Gen 1 Alternator is going south. Will run in to work as usual tomorrow and if it acts up will dump it.

The CUCV alternators are different that Civvy units in that they use "isolated ground" units. This means the internal electricals are "isolated" from the case by fiber washers. Also the idiot lights must be working for the alternators to excite.

Has your mechanic ever worked on CUCVs before? Many of us have had to learn ourselfs and teach our mechanics.

You can test the wiring to see if it is in working order. It has been covered many times.

We will cover it again.

1. First you must make sure your batteries are fully charged and can handle a load. Autozone can load test them.

2. Unplug the two-pin plug from the alternators

3. With the key OFF check for voltage at the small RED wires. You should have a constant 12v on the GEN1 (driver side) and 24v at the GEN2 (passenger). You will not see any voltage at the brown wires.

4. If you do not have voltage at the RED wires you have to trace the circuit and find the problem

5. With the key ON check for voltage at the small BROWN wires. You should have a constant 12v on the GEN1 (driver side) and 24v at the GEN2 (passenger)

6. If you do not have voltage at the BROWN wires you have to trace the circuit and find the problem

7. If the above test works, then you need to remove the alternator and have it tested/rebuilt.

Check the wiring and then report back.
______________

 

[doghead]

My Son, Daughter and I had a great time troubleshooting Charging system together.

Awesome!

 

[Warthog]

I guess I do need to watch what I say, as my words come back around when you least expect it.

Glad you found my old checklist and it helped you troubleshoot your alternator.

Great that you had your kids help.

 

[cook6657]

donally1 thanks for the check list just what I needed. I have an 85 m1008 with 4000 miles on it. Drives great no issues. I installed a 12,000 lb winch today and after spooling it back up my gen 1 light is steady on. Have you guys ever seen a winch burn up an alt? I will check the wires, but I am sure the alt is fried.

 

[Warthog]

Welcome to the site

The alternator was probably in need of repair anyway and the winch help it over the edge. The trucks are 30 years old and stuff doesn't last forever

There are a lot of helpful info in the CUCV Wiki and the CUCV Help Threads sticky. I have written many CUCV charging system threads.

http://www.steelsoldiers.com/showthread.php?123199-CUCV-Helpful-Threads

You may want to start your own thread as we help you work thru the issues you have with your truck.

 

[cook6657]

yeah that is what I am thinking. I was converted to 12 volts before I got so I need to do some wiring to get both alts functional. I will run a few test, but most likely rebuild both of them. Where is the best place to get a quality rebuild kit? Can I get kits that beef them up more than factory? Thanks for the reply Warthog. I was all excited after installing my winch. I had my wife holding the break in the truck while I was in the car putting tension on the cable. I Hooked the winch into the bumper, and was admiring my work and she says the Gen 1 light just came on. Old green couldn't even let me celebrate for a minute. Ohh well back to working on it

 

[MarcusOReallyus]

Hey, neighbor, welcome to the site! I'm just north of you. Shenandoah Farms. You're about a half hour from me. There are quite a few of us here in the northern Virginia area.

 

[cook6657]

Sweet do you guys have spots to wheel in the area. Im right around Flint Hill on 522. I am also helping my brother build a Jeep. We were planning on riding GW. It would be cool as **** to trail ride with other cucvs

 

[Warthog]

Please start a new thread instead of hijacking this one. What does wheeling have to do with alternators not charging?

 

[dlayman21]

Can I replace #1 alternator with one for 78' Cadillac or are just the parts from one able to be used.

 

[Westech]

the whole thing can be replaced with a civy unit. The Driver side is grounded to the block and a isolated ground is NOT needed.

 

[dlayman21]

OK, thanks. So get an 100 amp alt. for Cadillac and should be good to go?

 

[doghead]

You'd be better off simply rebuilding your original.

 

[cook6657]

The hardest part of rebuilding the alt is getting the rear bearing out without cracking the housing. Smooth sailing after that part. I just did both of mine. I cracked my housing on one. Lucky for me I had a parts alt. Cracked that one also. Ordered a crusty one off ebay for 25 bucks and third time was a charm.

 

[Warthog]

The hardest part of rebuilding the alt is getting the rear bearing out without cracking the housing. Smooth sailing after that part. I just did both of mine. I cracked my housing on one. Lucky for me I had a parts alt. Cracked that one also. Ordered a crusty one off ebay for 25 bucks and third time was a charm.

You should always use something to support the case when removing the bearing.

Here is a post in the CUCV Helpful Threads Sticky.

http://www.steelsoldiers.com/showthread.php?60299-CUCV-Alternator-Rebuild-Question

Post #17 shows what I had on hand when I was rebuilding an alternator

 

[dlayman21]

Is this an isolated ground alternator, it's located on drivers side.