Could this be my alternator

[SILVERPAGT]

Last weekend my battery gauge was in the middle then dropped to almost the low mark so I got it tested at autozone on Sunday, they told me it was putting out 64 amps or whatever they measure it in. They said it was fine. Well last night I had the rear window defroster on and the windsheild defroster on high along with lights, radio, and wipers. The battery gauge dropped slowly so I went to Advance to have it tested, but this time with everything on and it read that it was only putting out 46 amps. I bought an alt. last night but just want to make sure this is what is causing this.

Thanks
Bill

 

[n0v8or]

Alt is a good bet, but a slipping belt could cause the same effect.

 

[warment]

Just hook a voltmeter to the battery terminals with the car off (battery should have over 12 volts), then with the car running (battery should have over 14 volts).

If the voltage with the car running is lower that when the car was off, you have a bad alternator.

Bill

 

[SILVERPAGT]

Well I changed the alternator today and still have the same problem. Guess tomorrow a friend of mine is coming over to see if we can figure it out and yes I'll be checking the volts too. It has something to do with when I have the defrosters on. I was watching the belt to see if it was slipping ,but the only thing I could see was that the pulley on my ac compressor would stop then start. Think maybe I'll try a new belt seeing as to who knows when it was replaced. Thanks for the reponses so far. Oh yea would a bad belt tensioner cause this?

Thanks again
Bill

 

[1992 2.3LX]

don't listen to those autozone wahoo's.
i took my battery in to get tested because the car wouldn't start.
they told me it was fine but i highly doubted that it was. so i went and pulled the optima out of my buddies truck and hooked it up. and she lit right up. went out got myself an Optima and she has lit right up ever since. But there was nothing wring with my old battery

 

[n0v8or]

Yes,a bad tensioner could allow the belt to slip.
I would paint a couple of white stripes across the back of the belt, and a white dot on the outer edge of the alternator pulley, to make it easier to see if there is slippage (check with the headlights On).
The defroster turns on the A/C compressor. If the belt is slipping, it will be worse with the load of the compressor added.