Engine/Transmission (1994 - 1998) Generator light on

[Crupper]

The generator light came on, started checking all the the things I thought might cause a problem. I found that the posts on the battery on the right were just black & hard on the post and in the cable. Hard to get off, But cleaned all posts the cables. As I look back I think I have been using one battery, for I don't know how long, any way the GEN light is still on. Did I cook something by only using one battery? It's a 96 2500 SLT 4x4 (made in Mexico,on the door post). Help, Fair week coming up and I need the blame thing not hooked to a battery charger.

 

[RichK]

May need a new alt or brushes. I just had to put one on my '96. I got about 260K miles out of it.



Good Luck!



Rich

 

[Howard Durand]

Since you don't have any other problems, such as no tach, I would guess the alternator is in trouble. Remove it and take it to an auto electric shop where they can test it for you.

I have never opened up an alternator but don't think they have brushes.

 

[RichK]

Hi Howard/Crupper,



They are in fact rebuildable. You do need to be careful about shaft wear when the brushes go bad.



See the following link...

http://www.fixinrams.com/id12.html





LarryB carries the brushes too. http://www.fostertruck.com/alternators.htm







Rich

 

[Dr.Bob]

i replaced the brushes on mine, got them from local gen shop for about 6 bucks.

 

[Crupper]

Hi Howard/Crupper,



They are in fact rebuildable. You do need to be careful about shaft wear when the brushes go bad.



See the following link...

http://www.fixinrams.com/id12.html





LarryB carries the brushes too. http://www.fostertruck.com/alternators.htm







Rich

Rich
Got it on the bench and took the back side off and the burshes out, and the shaft has alot of wear where the brushes ride. The rear one is quite deep. Better replace it huh?

 

[Missouri Mule]

Have your batteries voltage checked and the batteries load tested.

 

[RichK]

Yes, If the shaft is pretty bad I suppose that's best. I found a local place here in So Cal that does good work on alternators. I'm sure you can find that up where you're at too. If you're in a pinch, you can probably just do brushes for a short term deal.



Best of luck,



Rich

 

[Crupper]

Installed new alternater, "GEN" light is off but only charging 12. 04 amps into batteries with high beam lights on. With lights off 12. 22 amps. The dash gage has always been near 14 amps before, now shows just above the middle mark between 8 and 14. I'll find out tomorrow and I'll still take along the charger. Just not a high a reading as it was before. .

 

[Crupper]

PS:

Old alternator failed all three tests @ Schucks and they had one in stock, It tested OK and they talked me into a belt too. $209. 78 total

Thanks for all the help.

 

[Howard Durand]

Interesting thread. I stand corrected on the brush issue.

 

[tp0d]

Installed new alternater, "GEN" light is off but only charging 12. 04 amps into batteries with high beam lights on. With lights off 12. 22 amps. The dash gage has always been near 14 amps before, now shows just above the middle mark between 8 and 14. I'll find out tomorrow and I'll still take along the charger. Just not a high a reading as it was before. .

That isnt a charge meter on the dash, its a voltage meter. What did you use to take amperage readings, you would have to detach the alt lead and tie it into an ammeter in series. .



-j

 

[Crupper]

That isnt a charge meter on the dash, its a voltage meter. What did you use to take amperage readings, you would have to detach the alt lead and tie it into an ammeter in series. .



-j

Your right about the volts meter "I knew that" It was volts I ment, at my age it's hard to change!! I didn't check the Amps just looking at the volts gage and noteing that it wasn't getting up to 13+ volts like it did before everything went gunny bag. Didn't get a chance to even look at it today. There was instructions that came with the Alternator that I found on the bench last night that tells how to run a check on the system, I'll do that tomorrow and maybe that will tell me whats going on.

Thanks, Crupper

 

[tp0d]

My basic electricity knowledge is quite rusty, but from what I can recall, when brushes wear out they arc more (and longer) on the armeture, which can throw off the voltage reading on an analog gauge. Mebe this is why you're seeing the high readings. . hmm, mine seems to be doing that more, mebe I need a brush change. . hmm. .

-j

 

[McCRam]

Don't forget your grid heaters will be cylcling when you start the truck. I just replaced my alternator, and couldn't get 14volts until I disconnected the grid heaters and let it run for a bit.

 

[Crupper]

After driving a few blocks today the "GEN" light came back on and stays till I turn the key off, turn the key to on again - a time delay - and the light comes back on. Started out this morning with battery voltage at 12. 22 volts, shut it off this evening and still has 12. 22 volts in battery after driving around town and starting about 6 times, It's got me beat! I'll have to take it to a shop with some test equipt, I guess. Thanks everyone!!