Alternators......

[Brokeblazer79]

My rig is doing something weird...... I drove it last weekend to San Deigo and on the way back my headlights started getting bright than normal and flickering along with my dash lights. I think it might be the voltage regulator. But I am getting comflicting stories as to if I can change just that or or replace the whole alternator...... any ideas ????

 

[dbreid]

Test your battery as well. Make sure your battery is actually able to take a charge. With the truck off, test and make sure you are getting 12.5V.

 

[dyeager535]

What's your voltmeter or gauge tell you?

As mentioned, check your battery, but don't assume it's the regulator if you haven't proven the alternator isn't holding a fairly constant voltage.

 

[Brokeblazer79]

the gauge jumps to about 14 volts at mid to high rpms........ The battery is holding a constant charge, I have no problem starting the truck..

 

[dbreid]

What is the voltage with the truck off? If the voltage is high (14.4 etc) that just means your alternator is working. Not that the battery is any good. Search for recent posts from me. I learned this lesson the hard way. I had a brand new Yellow Top that wouldn't take a charge. Three dead alternators (new ones, mind you) I figured it out. Bad battery....

 

[Brokeblazer79]

Well I swap the battery out of my Trans Am and I still have the same problem.... So I am assuming it's the regulator..... Thanks for alll the advice....

 

[dyeager535]

You can buy a rebuild kit for about $20 for the 10/12SI alternators, which includes the regulator.

Still going to want to verify 100% that the alternator output is fluctuating, and it's not something like a loose or bad wire.

 

[Mike D]

You are right, when your lights flikker from brite to normal to brite usually indicates a regulator that went bad ( making the alternator put full voltage and amperage into the wiring system and the battery ). Have your battery checked after you fix the alternator, it could have cooked the battery plates. Check and add distilled water to the battery because it will need it.