Battery gage fluctuates w/ AC on

87quad · #1 (**permalink**) 08-22-2003, 07:46 AM

First, it is great to find this site!~ I can't believe I didn't find it earlier.

RE: Alfa Romeo Quadrifoglio (Spyder) 1987

QUESTION: Whenever I turn on the Air Conditioner on, the battery gage goes down (to under 12amps). My mechanic tells me that the alternator must be replaced. I want to double-check before I put up the money for the replacement. ANy help will be appreciated.

**papajam** · #2 (**permalink**) 08-22-2003, 10:20 AM

Welcome 87quad!
Adding a load such as the A/C when the engine is idling will tax any charging system. I would verify system voltage with the A/C both off and on at the battery with a voltmeter at idle and 2000rpm since the accuracy of the dash voltmeter may be in question. If the voltage doesn't go up to at least the low 13v range at 2000rpm, I'd say your mechanic is right. You also might consider taking the car to an auto electrical shop where they can properly loadtest the alternator in situ.

87quad · #3 (**permalink**) 08-22-2003, 10:30 AM

THANKS!.. I will give it a try. Appreciate the quick response. I'm sold.

AlfaRomeo1750 · #4 (**permalink**) 08-27-2003, 11:13 PM

Howdy and welcome to the Alfa BB.

I Would like to say that I agree with Papajam on this one. I also Have an 87 Quadrifolio, and when I turn on many electricals at once the battery light will come on faintly, and the gauge will dip, but when I put on the volt meter and have some one revv the car.... everything checks out.... Usually when an alternator goes.... you get more blunt warnings. Or at least that has been my experience.

Besides as we all know, the Pod dash gauges in the later spiders are notorious for being faulty by this time in their service. So no worries.....

Best of Luck....

Martin.

71 Spider Veloce

87 Quadrifolio Spider.

87quad · #5 (**permalink**) 09-09-2003, 06:47 AM

Thanks guys. I had the alternator tested and, indeed, the thing was bad. Had it replaced and finally get appropriate readings from battery. However, the gage still shows dips (which don't count, since the readings are steady--meaning no drain in battery)--weird, but I can live w/ it.

Now, to the next project. Dead heater blower (I think). Before I begin tearing up the inside to find the motor (to test), can someone tell me where to find it (under hood, inside). Sounds stupid, but I have a bad habit of starting in wrong place.

Thanks...