When I drive my 1980 12a at night the lights dim and radio cuts out when I tap the brakes or drive in reverse. My guess is the alternator is not giving enough juice. I want some thoughts before I yank it out. Also should I upgrade it and If should what should I use?

 

Start your car and disconnect the battery. Don't let the positive touch anything it will spark up. Cut on all your lights and step on the brakes and put into reverse. AC on to for a little more drain the fan on high. If it cuts off than its your alternator. Also, If you disconnect your alternator your tach will cut out and your voltage gauge will start working. Atleast if it is a pre 80'. I would go with a higher amp alt. wouldn't hurt anything.

 

I did what you said and it cut out on the last thing I could turn on and that was the rear defrost. Althought before that everything work well except for the stereo. I changed the alternator with one from a parts car and the same thing. I guess it's possible to have 2 bad alternator seeming they are both old. But before I locate a higher output alternator I'm going to check all the wiring. What do you think?

 

go get the alt checked at a parts store. they do it for free. them worry about other things.

 

Good Idea!

 

Get the battery checked too... they'll do that for free usually as well.

A bunch of people have had similar problems around here lately that have turned out to be bad grounds... So if your alt. and battery are ok I'd check your grounds next....

 

I will check the battery to because it's free. The battery is only 4-5 months old thou

 

I didn't go to a car place but even better. I borrowed all the test tools from a guy at work. He restores vintage and classic cars so he hads tools galore. Tested the battery and the alternator. The battery is fine and the alternator is only puting out 13volts. The problem is not only the alt. but I tested the ground by using a jumper cable from the negative of the battery to body and the problem wasn't there. So basically I need to reground the cable because the cable is fairly new and I will replace the alternator soon.

Thanks Guys

 

Consider this if the bucks are thin...most miss it going over the FAQs page for some reason...

"Economical" Alternator Upgrade...