Hi all,
Yesterday I got in my car after work and started it up and all of the idiot lights on the logicon stayed lit. I did some searching on the site and saw that it was probably the alternator. Did the basic tests and saw that the alternator was putting out 18 - 20 volts. Probably not bad.

So, I pulled it and took it in to Auto Zone to have it tested for a second opinion. The tech hooked it up and turned on the test and immediately it made an awful noise and started blinking FAIL. Tech tells me the bearing is fried. LIE! I grab it and say 'look how smoothly it spins'. Tech shrugs and says 'but the machine says it failed...' So much for my second opinion.

I then decided that it was the voltage regulator and handed it off to an alternator service shop that came up with 'failed voltage regulator causing overcharging'. So 5 hours and $80 later, I've got the rebuilt alternator installed and things are working normally. Almost.

The logicon lights that were once nice and bright before ignition are now dim... save for the hatch, door and check engine lights. Is this bad? It makes me worried this change.

Any suggestions?

-Mark

 

Um... 18-20V in the electrical system is Bad - even 15-16v is enough to fry things.

What's the standing (engine off, ignition off) battery voltage? If the regulator went bad, it's possible that the battery largely discharged itsself through the regulator while the car was off. It should be 12.7v or so.

If it's correct, you may have damaged something in the cluster. But check the battery voltage first.

-=Russ=-

 

Sometimes when your charging system isn't up to par, the regulator will overcharge and you will get a spike in your running voltage. It's happened to me, and it was because I was using a **** battery, which eventually died and could not be charged to work, had like 6v, etc.

Try swapping batteries and see if it will still put out that +15v, if it does then you will probably need a new alternator. You don't want to go over ~14.6v...that's when **** starts to fry.

Good luck,
James

PS: An easy test to see what an alternator is putting out is to connect a DVOM to the B+ lead and ground the other connector, read the voltage. It should be above 13v, preferably around 14. Just a little extra info.

 

Replace the cluster lightbulbs and report back!

 

I had a similar overcharging problem a few years ago. I figured it was the alternator (internally regulated) but it was not. It turned out to be a bad ground to the alternator. I ran a short piece of 8ga car audio ground cable from the alternator case to a better grounding point - problem solved. I wanted to slap myself b/c it was such an easy & stupid problem and went out spending $$$ instead of investigating the easy easy stuff.

1st rule of checking electrical gremlins - CHECK YOUR GROUNDS! A few minutes w/a meter is alot cheaper than throwing parts at a car. In my case, scrap 8ga was alot cheaper (free) than alternator...