Problem just started with my 2000 V10 Excursion, voltage fluctuating and battery light flashing on and off approx 2 times a second. With head lights on slight fluctuation coinciding with batter light. Suspecting a voltage regulation problem, is this built into the alternator of is there an external unit? New battery installed month ago and is fully charged. Is there a way to confirm where this problem is? Many thanks for any suggestions.

 

You could search and find your answer.... You could search the engine forum for your engine. Just from experience: try removing the negative terminal off your battery while the engine is running. If the engine dies or runs rougher then your alternator is bad. Searching is your friend and you can learn a ton while searching.

 

put a multimeter on so you can see if its voltage or amps. If the voltage is constant its not a voltage spike. If voltage is wildly oscillating then its your regulator. I don't have a v10 but I believe they have an internal regulator. Most newer vehicles do.

If the voltage is constant then I believe your problem could be a bad ground, so check your engine block and battery ground straps, and make sure the body is adequately grounded as well.

 

Yoy should have 13+ volts at idle with fans/lights off, if you don't have a volt meter with dc, home depot or radio schack has a $10.00 version, hope this helps.

 

buy just about any automotive magazine and harbor freight will give you a free one with $10 purchase. Just as good as the $10 one from any other store. lol

 

I had the same problem a couple of years ago. Swapped out the alternator with the voltage regulator attached to the back of it and the problem is gone.