Today has been a heckuva day. This morning I went out to start her, but she made the 'ticking' "I'm low on battery" sound. I got it charged up, went to the gas station, filled up, and she started up fine. Went to class, came out, and she was dead again. Took it to AutoZone, they charged the battery to 13.4v (the manager was impressed). and tested my starter, and alternator. Everything checked out. I pulled out onto the road and noticed the (brake) and the Battery light came on whenever the clutch was out. They'd turn off when I'd use the blinker, breaks, etc. The dash voltage meter read 18 (!!!). I went to my next class, parked it, and came out after an hour to see the lights on again, but the meter was a tad above the halfway mark (9.5?) and the lights would stay on, no matter what. Driving, I smelt a shorted circuit. Is my alternator or my voltage regulator bad? Bit stymied by this.

 

I would guess it is time to buy a multi meter

Get some real world numbers !!!

Something is wrong some place could be as simple as poor grounds

Be nice to know maybe just what vehicle is being a pain!!

Looks like you have a over charging condition with enough of a load it drops to normal the lights go out.

Quite possible it was fine when tested or the person who did the testing was a idiot!!

Could be either!!!

 

I've got a multimeter, just didn't know where to start. Battery? Do you have some simple, basic steps outlined?

Its a 1993 4Runner with the 3.slow.

Thats what I'm thinking, or maybe the overcharged battery somehow caused a relay failure.

The guy who tested was the store's manager, so I'd hope not, since this is one of their advertised services.

Shame too, the guy was real nice and loved the 4Runner '

Bit of information I forgot to include in the OP. I had my hood off for painting, and it rained. Oops.




The alternator is also the original alternator....

 

By rain you mean a few sprinkles ??

Then maybe a few inches ??

The battery is always a good place to start.

Measure at battery terminals engine off should be @12.5 VDC engine running no load on alternator @ 14 VDC With the most electrical load Head lights, 4 way flashers ,Blower Motor it should never drop below 13 to 13.5 VDC.

I think the light will trip about 14.5 VDC in a over charge condition.

A voltage regulator which is inside the alternator going bad could vary between a no charge to overcharge condition.

Poor ground connections could be a the battery terminal or the other ends.

You have a electrical issue now to find the cause

Take your time .

 

How the charging system works, test points, what voltages to expect are covered here.

Concept same as V6, altho wiring color-code and location of components may change.

Pls report back what should be expected that you are NOT getting and what you are getting.

 

Ok, the alternator went bad. I smelled around the alt and it smelled toasty. $120 at AutoZern