I noticed today while driving that the battery voltmeter on the dashboard went down close to red range when I had my headlights, defroster, and vent heater on. This has never happened before. Usually, if the headlights are on, there is a slight increase. The battery was just put in last year. My car was recently broken into and the radio stolen. I'm wondering if some climate control wire could have been damaged that is causing this. Any thoughts? Thanks.
Kevin

 

Most likely your alternator is on its way out. It should be able to cope with having those accessories on. You can have the alternator load tested at most car parts stores for free. When buying a new one, be sure to get a good quality rebuild, not one of the cheap ones from the discount places. I once got a Masterquality alternator from a discount place, I then proceeded to replace it two more times within a year with free replacements under their lifetime warranty. In my opinion, the extra 10 or 15 dollars is worth not having to replace it agian, not to mention getting stranded.

Good Luck

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82 T/A 305/TH350; soon to be 350/T-5

 

Thanks.

 

I realized that a couple of days before yesterday's electrical problem, I noticed that the battery voltmeter was a little higher than it usually is when my headlights were on. Why would that be? In general, when my headlights or rearview defroster are on, there is a slight increase. I know there is
supposed to be a slight increase but why? Because the alternator is working harder and puts more current in the battery?

 

In all of my vehicles, there is a decrease in bus voltage when i have alot of accessories on. If you have a slight increase, that may just be your regulator over compensating for the load. This could be the start of a problem, though. I had an alternator in my moms lumina minivan that was overcharging, and melted the big wire going to the alternator. Nearly melted some other wires in the harness as well. Just have the alternator tested, I'll bet they find a problem with it.

 

I got a cheapie alternator and my V's drop down in the 9-10v range at idle w/ headlights on. If I idle for a long time it will suddenly kick on up to 14v's otherwise my lights flare as soon as i get outta idle. Been like that for years now so it really dosn't bother me, but I shudda got one of those Duralast Golds instead.

 

It turned out that the throttle position sensor voltage was high due to the idle air control needing to be adjusted. The throttle body was also very dirty.