appatula

I've searched and have not found a spot on answer for my problem.

I just noticed a dimming in my lights when at idle. I'm not sure if it has always been this way but it bothers me. My headlights seem to dim down at idle but if I touch the gas pedal they intensify then go back to dim, this seems to be consistent throughout all of the lights in the car. I have read that the OVP relay, Fuel Pump relay, or voltage regulator could be causes? What can we rule out here guys.....

vili1982

I think your alternator may not be recieving proper power while the car is idling, in general when you step on the gas pedal you are increasing the overall rpm, which activates more alternator power. Check the connections around the alternator see if anything is suspicious.

myfirstbenz

have your battery load tested, and also check to make sure that your voltage regulator is not worn out. Your alternator will last a long time, but the voltage regulator can be cheaply fixed.

appatula

Thanks guys I will check into the battery and VR

carlson03

Hey, did you ever solve this problem? I have a similar problem and its annoying at night....I was thinking about replacing the voltage regulator since its only about 30 bucks...

STLe320

It seems like this would be an alternator/battery issue.

shdoug

Yes, that's a good idea. The regulator contains the brushes and as long as the bearings are good in the alternator you should be fine.

forcedawd

I had the same problem a while back. Replaced the regulator and no problems since.

jeffreyli86

Anyone got a pic of the voltage regulator? I was just going to replace my alternator with a bigger one because my ICE is making my rpm dance very slightly at idle.. I'll change it just for the sake of it and see how it goes..

GEDaggett

Put a meter on the battery leads while the car is running and check the voltage with the lights on it should be above 13.5 volts if not you have a bad altenator.

myfirstbenz

http://www.mercedessource.com/node/243

Jeffrey, you might also want to consider installing a capacitor for your sound system. I had a similar problem and that solved it.

STLe320

I have a cap...but they're actually not what they're cracked up to be. I'm about to get rid of it though, and do the BIG 3 mod.

carlson03

good price on that voltage regulator...thanks!

ps2cho

The voltage at the battery with the engine running and everything else off and fully charged battery should be 13.0 to 13.8 Volts. Domestic cars will be 14 to 14.8 volts.
With the engine at idle, check for AC voltage. It should be less than 1V. If it is more, than the rectifiers are bad in the alternator. Now back to DC volts at the battery, turn on the lights and the AC fan to high. The voltage will drop but it should stay above 12.5V. Rev the engine to 2000 RPM and the voltage should go back up to 13.0 to 13.8 V. If not, check the alt belt first. It should be tight enought that you can't turn it by hand.(Be careful, it will be hot). If the belt will slip when turning it by hand, it is toooo loose. Tighten it and recheck.

Quoted from here:
http://www.mercedesshop.com/shopforu...d.php?t=115014

I would check it soon as next thing you know your battery is dead and your stuck on the side of the road. <--- Yes happened to me. I just had my alternator changed about 4months ago as it was toast.

Rio Z Lander

mine did the same befor i rebuilt the alternator and this was after i got the new bat!!!! it would be best to have both tested