AC pulls hard on alternator

[btully]

My BII's AC works ok as Im driving down the road but when I stop at a light my volt gauge goes from about 13-14 to about 10 or less; and the AC fan barely blows. Im not sure if this is normal; or if not, how I would go about fixing the problem. Even my blinker makes my volts go up and down (very slightly though). Does anyone have any ideas that might help? I've had to change the alternator twice since Ive had the truck, and the problem still remains. I am completly in the dark when it comes to electrical issues.

[greenmachine89]

Check the fan that blows in the cab that might be going out. You voltage gauge will move when things are on but if everything slows down then something is taking too much power!

[Bob Myers]

Sounds like alternator has issues. Have it checked to see if the amperage output is within specs. If the amperage output is low it will fluctuate the voltage output drastically.