so my GEN light came on while i was going onto post this morning and at the same time my voltage gauge dropped drastically, so i turned of the radio.... heater.... lights etc. and got work just fine. when i left at noon the light was off and the gauge read fine. i turned on all my lights and every thing else i could think of to draw power and everything looked ok. any ideas on why this might have done that?? it really has me stumped. thanks in advance!

 

It is your brushes on the alt. The shaft gets worn and makes it so that sometimes they make contact and some times they dont. It wont go away by itself. You will either need to put new brushes in (about $15) or get a new alt. The brush change will buy you some time but they will wear out quicker because the commutator is already worn where the brushes make contact. If you are handy and have a lathe you can recut the shaft and it would be fine. I hope this helps you.

 

Make sure you battery cables are tight and clean I had the same problem.

 

Brushes. same symptom happened this year on m 95.

 

Having same problem with my 95 chevy PU. New battery and alt an still same problem. LOW Volt gauge and hard starting. Maybe armature? in starter. Maybe be bad cables?

 

well thanks for all the input. guess i'll look at getting a new alt. so i have one if it happens again. it's just wierd that it hasn't done it since.... i dunno.

 

If it is the brushes it will get worse over time mine did it for 3 months before I put brushes in it. It would be worth checking over the wiring looking for a bad or loose connection. When mine would do it was when the engine was cold and then intermitten when worm. When it was warm usually a quick rev of the engine would get it working again untill it got real bad then I figured I better fix it before I had a dead battery.

 

Don't get too hasty about getting a new alternator. If there is a large, continuous load (like the grid heaters) the PCM will kick the alternator off line, and reset when you start the engine the next time. When you start it in the morning pay attention to the grid heater cycling. If it stays on (low voltage displayed) and doesn't cycle off you may have a malfunctioning relay or two.

 

well it still hasn't happened again. and i disconnected my grid heater from the battery as they stayed on one day and killed my batteries. got the new relay that mounts on the inner fender but that didn't work so i left them unhooked. i checked out all the wires and all seems well.... could it have been condensation or something like that??? it was cold as heck and raining the day before it happened and just started to warm up when i was headed to work. just an idea.....