OK, this is the deal. Car has been fine and running fine. Has recent new battery. All the sudden (when it idles and drives) now the voltage seems to be pulsating up and down. I have not put a meter on it, but it seems to be going from 10V to 14V is my guess.

Any of you have any ideas? Is it the over voltage relay bad, voltage regulator, alternatorm, battery? What do you think?

Car starts and runs fine. Battery is charging, etc.

__________________
Mercedes C43 AMG
Porsche 911 Twin Turbo
Land Rover Disco II
and some other interesting stuff

I just fixed that problem with my wifes car, my hands are even still dirty. Its your voltage regulator acting up, or it might be a bad connection on your newly changed battery. As far as the battery is concerned its the best way to charge it. The rest of the car and oncomming traffic won't like it though.

Is that like a $30 part and something I can do with hand tools in less than 30 minutes? Or, do I need to remove stuff and get real dirty?

__________________
Mercedes C43 AMG
Porsche 911 Twin Turbo
Land Rover Disco II
and some other interesting stuff

Yes,yes and no.
Very simple. Do a search!

__________________
J.H.
'86 300E

It is just plug and play. You do have to go underneath the car. A Bosch one is $50, but a knockoff is $15.

glenmore
1991 300CE
1990 LS400

abalto, I had a similar problem with my Benz, flickering lights. Yes, it was the voltage regulator but that was discovered after the battery light started glowing at idle. It's an easy fix, DISCONNECT THE BATTERY "+" for safety, raise the front of the car (my "large frame" won't fit), take off the belly pan and there was the alternator with more than enough room to get to it. Two screws and it'll fall into your hands, new one screwed in, you'll have to hold it in place, and you're almost done. Total time to replace mine, not counting the smoke break, 30 minutes, includes raising the car and dis/reconnecting battery.

On the old one, one brush worn even with the main body, the other brush has 1/4 inch remaining, yup, worn out. Why can't other cars be so simple and easy to work on??

__________________
1991 300SE (my ride, 279,000 miles, looks almost new
1954 Cadillac (21 yo son's car, he bought when age 15)
1972 SeaBird 19 ft runabout (old but solid, slant six, Volvo sterndrive perfect condition, undergoing complete overhaul and refit)
1998 Toyota Rav4 (my sons daily driver when he is in the Continental US, PROUDLY serving in US Navy)