this thread pertains to these stats - '97 2500 Auto 4X4 club cab Long bed

My brother is heading up through WV and was going through snow drifts last night and his gen light came on. Right now he is running and the volt meter shows around 13 - 14 volts while he is driving. Water temp is normal and the defrost works. So the belt is intact. He is running his radio, lights, defrost and the volt meter is not changing. He is curious what might be going on. He is mechanically inclined, but this one has got him scratching his head. Could anyone share some knowledge that might help him out? He has not turned the truck off yet so he doesn't know if its a battery issue or not. Thank you for the help.

Swordfish

 

If his volt meter is where you say then it is charging. If was not charging it would be 12.5 or less. If his charging light is on then it is contradictory. I would suggest putting a volt meter on the battery while the truck is running. If it is over 13v it is charging.

 

Lifer,
My thoughts as well, but I want to cover all angles and anything we haven't thought of. Thanks for your reply.

 

Mine came on last year and it turned out to be a battery connection. Maybe some snow got up in there and something got wet. If it is throwing a charge then it has to be a connection of some kind.

 

If it is not charging it might be possible that the crank position sensor or its wiring was damaged or the connector got water in it. The crank sensor on the 12 valves is on the front of the engine and reads off a notch in the crank pulley.

 

I had something similar with my truck. The gen light stayed on all the time it charged under load on the highway but when you came to a stop light the voltage gauge would fall on it's face.Changed the alternator. I never bothered trying to find what went wrong with it though.

 

Thanks guys I appreciate all of your help. I have passed the thread on to my brother. Hopefully your suggestions will be of help to him. I will try and post back with the results.

Swordfish

 

My gen light just came on for the first time since ive got the truck, It has been charging normal tell tonight, always at 14 stedy. I drove it to the store in the morning and the light wasnt on and was right at 14 then i parked at a family members house and the truck sat for 8-9 hours. When i started it up to go home at night, it went down to around 11-12 like always but never came back up, gen light came on about a 1 min later and stayed on. I drove home the whole way "10-15min" it stayed at 11-12 the whole way never moved. I turned the truck off and back on, gen light went off but still aint charging right?

My first thought is alternator is not working right, but seems strange that it happened all of a sudden like that.

any thoughts

thanks for any help, matt

 

That is about what happened to my truck. I rebuilt the alt, including diode pack and slip rings just about $90 at a rebuild shop. Works good last along time.

Floyd

 

If you do have to replace the alternator don't fall for the auto parts lifetime warrantied Chinese junk.
Many are bad right out of the box and even if it isn't they don't last.
The OEM alternator is very high quality, have it rebuilt or replace with the same.

 

ok, ill give it a bit make sure its the alt , then look in to a rebuild or new quality unit.

thanks for the info, matt

 

Is the Tach working?

If you show 12v and no tach, it's probably your crank sensor.

 

ya, everything else works as it should.