Posted on 07/04/2014 6:52:19 PM PDT by djf
It’s the voltage regulator and it is almost certainly part of the alternator. Best option is to replace the alternator. I once had a weird problem where my rebuilt alternator would shut-off when it got hot. So if I took it to get a warranty replacement, they would test it, and it would look fine (since it wouldn’t be hot). Drive it for 15 minutes, it cuts out - but they can’t do that on a test stand. So, I figured the best option was to hard-fail it. So I plugged in 120V to the voltage regulator terminals (the smaller wires) for a couple of seconds and nothing happened. Then I ran the alternator on the car and the voltage immediately zoomed up to 16V (just like you)...I had popped the voltage regulator electronics and it no longer regulated. At that point, I took to to the auto store and got my warranty replacement.
In your case, you’re killing your battery with such a high voltage, and also stressing all the electronics in the vehicle - get the new alternator and be done with it.
You’re probably right.
But the thing is I can’t figure out why, with the new battery, the first time I started it the light came on almost immediately - and the voltage tested 16v.
But EVERY TIME I started it since then, it seems to take more and more for the light to come back on. I just drove it to the mailbox and it didn’t come on!
Don’t know...I’ve never understood those lights anyway.
The light is current driven. It lights when it gets power from either the Battery side OR the Alternator side. If the current is balanced(zero) then it is off.
Are you sure you’re logged in?
“The battery was from 2006. So it was due...”
A bad battery can kill an alternator, just like a bad alternator can kill a battery
The circuit that controls the Indicator light is Usually part of the built in Voltage regulator. And it may be that this function is triggered by Conditions other than just under charging. If you are really at 16 volts then it sounds like you are overcharging. You really should replace the Alternator. Don’t buy the cheapest brand sold at the auto store or you may be sorry as they often have a high fail rate. I have had good luck with Duralast from Autozone.
Not suggesting it’s related or a problem, but since you don’t mention it, it’s a fair assumption it needs stated:
I once was in an auto parts store fetching bolts and a guy with a Jeep was having some issues. While I was there, the staff swapped out 3 different batteries...NONE would kick over his starter. They then blamed the starter and were looking it up to price it. I pulled him aside and asked him if he wanted to save some cash and trouble, as I heard/saw what the Jeep was doing when the last 2 batteries were clamped down and he turned the key. He said ‘yes’. I popped off each cable from the battery scored the inside of the clamp with my key, pressed it on hand tight and had him turn the key: Started right up. Bottom line: Corrosion is a dielectric (insulator). That goes for lead terminals, Weatherpack connectors and grounds.
What I’m getting at is you have a 20 year old car; don’t discount connection/ground problems in the process of your troubleshooting (I’m an expert troubleshooter, btw).
And don’t let friends that ‘say’ they know 12V systems modify/wire your car for that hot amp or other accessories...electrical problems that result sometimes are never solved...
Hmmm.
Just drove it to the mailbox (about 1/8 mile away) and...
No light!
So I got brave... drove it to a local store, about 1 1/2 miles away and...
No light!
It’s a Delco alternator that I put in about 2003. Has a lifetime warranty on it, but screw me, I can’t find the paperwork.
I think it’s OK.
;-)
Nice...just keep an eye on the voltage.
You might want to get something like this...it can be a lifesaver (or close enough).
http://www.amazon.com/Cigarette-Lighter-Voltage-Digital-Voltmeter/dp/B0092KVYGI
Re: your link
Why the hell do they call them cigarette lighters?
I haven’t seen a cigarette lighter in years.
.
LOL...actually GM, I think, called them Cigar Lighters, as they are big enough for most cigars. I still have cars old enough to have cigarette lighters - but it takes some work to keep them running.
My 1995 Nissan is on it's third alternator; thankfully, it's the only "mechanical" expense I've had in 19 years. As a result, I buy my Nissan new "presents" every once in a while. :)
Those mid-90 Nissans, they were/are good!
I got 237K on mine. I replaced the half/axles in the front and the struts in the rear. That’s about it! Oh, and the alternator.
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