[cobralini]

The car runs and starts fine but when I turn on the A/C the volts drop real low, it happens when I turn on the lights too. This is at idle when I noticed it.

[stang fanatic]

is your idle staying where its supposed to be??? if so, alt goin bad because its no longer pumoing out enough amps to keep up with the loads.

[MSTNGRCR13]

If the battery is old, then it might be one of the problems. However, if you have a voltage regulator going bad, this could also be the problem. You can take the car to your local Autozone and have it tested right there to get a better idea because everything electrical runs off the battery after the car is started and V/R might not be putting out enough voltage to power all the accesories while at idle. I would have to say that a good fix would be to change out the alternator as the V/R is built into it.

[stang fanatic]

all so true, but the regulators are internal and if its failing, then a new unit is a better investment...lack of voltage is due to low voltage from the battery. its amperage that matters....i can produce 14 volts, and run a car all day with just so many amps, but as soon as i load the sytem with an amperage draw...it starts to draw the voltage down because the draw is higher than the output...

[173speed]

If you have underdrive pullies..u may come across having this problem..from wat i understand with the underdrive pullies that i have the car doesnt really charge well below 2000 rpms....i have this problem during the winter since all i do is warm up the car...