Alright so here's the thing. I just recently changed my belts ( all of them ) my alternator belt was in pretty bad shape. So it runs fine, until I turn the heater on. When I turn on the heater it begins to stumble and even buck around for a bit, very violently. Same thing happens when I turn on my high beams. My interior lights slightly dim as well, so do my head lights. Is my alternator bad or is it something else. Thanks for the help.

 

Did you check if the belts are slipping? If your alternator is bad, then you know your ploblem.

 

Voltage would be the issue.

what does your voltmeter on the dash read???

It should always be above 13.5 volts just to charge the battery, and if it is lower than 12.6 volts then you are running on battery power.

Ideally it should be at 14.4 volts

 

On a some what same Q.
My Alt doesn't produce any power under 1k rpm(volt meter drops to battery only levels). Above it'll make 13+ fine.
Sounds like a bad alt?or is that somewhat common?