I'm having an issue with the electric going dim in normal temp idle.If I have the lights on or the blinkers or the wipers ect. but when I give it gas everything brightens up again.The volt meter in the car will drop down to 9 or 10.I have a optima red top battery and a 145 amp alt.Any ideas would be highly appreciated.thanks

How old is the alt?


There are a few tests you can do to see if it is the alternator.

The first is to set a voltmeter on "AC" and measure the voltage coming out of the back of the alternator. There will be slight AC, but if it is more then a few millivolts it means that a diode has failed.

also, I had the same symptoms when my regulator went bad.

If you feel like rebuilding the alternator, it is really easy and pretty rewarding.