Help! I have a 91 XJ that is in wonderful shape but whenever I use the heater blower with any other draw, lights etc..., the charge on the amp gauge goes way down. Down far enough that if I'm idling, it dims the headlights.....I am a fair wrencher but, this has me baffled for an answer.
Please, feel free to answer no matter how shaming it may be if it's simple. Do I need to change the blower motor resistor? Time for a new battery perhaps?

 

Check your alternator sounds like it may be going out also check the resistor if its drawing to many amps itll do that as well

 

I would suspect the alternator, too, but it could be other things. Stop by an auto parts store and have them check your battery and charging system.

 

Since you live in the rust belt, check your grounds. Copper corrodes too, just like steel. The XJ needs this TLC often.

If the alternator is bad, you can tell by removing the serpentine belt and spinning the pulley. Generally the bearings fail well before any electrical problem.

 

The jeep came from SC it has no rust, anywhere. All the grounds are perfect. Probably just time for a new alt. or battery.

 

"All the grounds are perfect."

fidy