300e dash dims and brightens, help!
 

Hello Board, My 300e is experiencing a problem that is driving me nuts! When I first start it up(at night) the dash is bright and after driving around for 5 minutes, the dash is yellowish, and not as bright as it should be, also my radio blinks with the volume turned up and when I open the drives door, the dome light flickers. I replaced the voltage regulator and the dome light bulb already and i have checked all my fuses(they are good). what could my problem be??

alternator?

Not sure if the 300E has one....
 

....but have you checked the rheostat (dimmer) control on the instrument panel? These get dirty with use and intermittent contact can cause your symptoms.

Since you replaced the regulator, I would suggest you check that for proper installation and function 'cause your symptoms are indicative of a faulty alternator, there is a slim possiblity that the part was defective when you bought it. Might also check battery cables/terminal connections for cleanliness and a tight fit

Alternator?? I have no dead battery problems! Any other culprits??

This is what I am thinkin'...if the alternator was dead, or very close to dead...obviously, you will have a dead battery after a while, which makes sense...but in your case...it seems the alternator is not quite providing enough amps/not performing up to specs and is almost on its way out...so although it is still charging the battery and powering your car electronics, it seems to be really struggling when you turn up the volume on your stereo, or keep the headlights running, etc. The battery is still being charged though...but maybe not being fully charged...but enough for starting the car, etc.

One way to test is to drive around your neighborhood for 5 minutes or so, until you see your headlights dim down as you described...and have the radio volume up or whatever electrical drain that you have in your car...then, pull over to the curb...put the car in park...and rev the engine up high...see if the lights come back up in brightness...