Hey guys,

1988 Pickup 4x4 V6 170K-miles. I noticed I was starting to get charge + brake lamps coming on when the engine is under load at higher RPMs like running through the gears to about 3500 up hill. Never come on until I get the RPMs up. Voltage too high?

I just finished replacing the alternator brushes with the OEM part and it still does it.

I also suspect this battery is starting to go. Will a bad battery cause these lamps to come on like this?

Replacing the brushes was so much cheaper than a new battery I figured I'd try them first.

Thanks.

 

Get a DVOM across the battery terminals at the load your specifying, and see what the voltage is. Also check it at the alternator.

 

this happened to me also. the next week or so i went out and started it and the alt started on fire, so it was a new alt for this guy!

 

Okay. Max voltage at the battery under the load described was 15.1. And I never saw the charge+brake lamps this time.

Min voltage was 2.7! Must have been when starting.

Guess I need a new battery. Funny thing that, I have had battery failures in ALL THREE cars in the same 3-month period.

At least I have new alternator brushes in the hoopty. There's < 3mm of showing on the old ones so it was about time anyway.