pmpn

89 GTA... my voltage drops everytime I turn on any electrical component. It doesn't die or anything but if I'm sitting idle with the blinker on my needle will bounce with it. It drops a lot when I turn on the hatch defrost too. Is this normal or happening to anyone else?? Thanks.

mw66nova

iTrader: (13)

why wouldn't it drop? it's taking power to do those things! that gauge is just showing you what the power is doing! it's completely normal, unless the drop is REALLY far.

BlackMagic

my car does it as well, but when i turn on the ac it just about dies when at a stop light in gear, but if i put it back in Neutral then the voltage goes back up. I dont care though, nver have the ac on......natural wind is a whole hell of alot better IMO

pmpn

I've never had a car that did that, plus the car has had electrical problems in the past...

Cali Z

Without accessories on, my voltage is normal, but drops slightly once an accessory is turned on. Usually, the voltage will go back to normal after a few seconds. If you have a small battery and run alot of accessories, you will probably have a hard time maintaining a good voltage and might have a few problems with dimming lights and such. But for the most part I would think it's pretty normal.

Dens71TA

iTrader: (5)

Its normal for the voltage to drop a little with each accessory switched on. You'll notice a big drop with the rear window defrost as that pulls 20 AMPs. Sitting at a stop sign with the headlights on, the heater blower motor on high, the radio on and the rear defrost on should show a big load on the volt gauge.

You may want to check the dash and engine to body/frame grounds. I know on my '71 T/A when I forgot to hook up the engine ground the temp/oil pressure gauge would twitch when the turn signal was on.

TAdan

Dens, you are absolutely correct. Ive sat at stop lights w/ the rear defroster, headlights, blinker, radio, and heater all going at once. I did notice a dip in the volts.

onebinky

iTrader: (1)

You need to verify the reading at the battery with a DVOM. The stock gauge is about as accurate as a dummy light.

rs80

The alternator is not capable of putting out extra amps when the engine is at idle. If you rev it up your voltage will probably increase. But when the car was new you probably didn't have this problem. Bad ground connections are a likely culprit.
Check that engine idle is at normal tune up specs. Check the alternator output at the local parts store, it's probably good. Check the alternator belt tightness. Check and clean the alternator and battery connections. A good idea is to use electrical connector grease. Start cleaning and greasing grounds.
Start with the big things first, battery to frame, engine, headlights, blower fan motor, wiper motor, defroster and go down to the turn signal bulbs.
When you turn the A/C on a solonoid should increase the engine idle. If it does not work and the engine rpm decreases below normal the altenator will not put out enough amps to supply normal accessory load.

bluegoose

RS80,
I dont understand when you start with the big things like battery to frame, ( I understand that) but the the rest, engine, headights, etc, what am I suppose to be checking?

Thanks in Advance.

firebirdjosh

iTrader: (1)

For a good clean, corrosion free connection.

bluegoose

Got it

Thanks