2003 GT Electrical Problem

[vandexa3]

For a couple of months now, as I drive, the voltage appears to get lower. The headlights dim a little or the wipers slow down.

Then, today after driving about 15 miles, and stopping at a store, I needed a jump to get it started again.

I got it home and did some diagnosing.

After some rest, the battery was 12.7 volts.

I started the engine and the voltage was immediately 12.4.

I let it idle and the voltage kept coming down. After about 1/2 hour, it was 11.6.

Could it be anything other than the alternator?

Thanks.

 

[EyeInTheSky]

Most likely is the alternator. I would either test it myself or call your local Autozone and see if they offer bench testing.

I guess you could check your ground, look for crazy shorts somewhere drawing huge amounts of power, check your belt and/or pulley on alternator to make sure it's all spinning correctly, but I would apply Occam's Razor here.

 

[meak]

Could be a alternator or battery. Alternator should deliver about 13.8V to battery after engine starts but if there is a problem with battery, then voltage will drop and battery will not get charge.
If you have a DC current clamp you can check if alternator is trying to charge battery. Also check cables for connections, including your ground connection.