Lamp light is on still!
 

My lamp light indicator came on and I had a bad voltage regulator. I replaced it and all the lights look good. Any suggestions on why it does not go out? May something simple like disconnecting the battery to reset it? This is a 1991 300SE.

Assuming you're talking about the lamp-out indicator, not the charging system light, right?

Check license plate lamps.

Also - sensor is very picky about bulb wattage. Make sure that all bulbs in rear lamps are of correct size. On my '92 300SE, the size (MB specifications) are visible next to each socket. May also be available in the owners manual. Even one bulb of the wrong size in a socket is enough to trip the lamp out light.

Diagnose which bulb by when the indicator comes on. If it comes on when you switch on the parking lamps, then it's one of the parking lamp bulbs or the license plate lamps. If it comes on when you step on the brakes, then it's one of the brake lamp bulbs, or the high-mount stoplight.

If have found that bulbs with brass housings also cause this problem. At some of the better auto parts stores they sell "OEM Bulbs" that have silver colored metal housings. I have always found these to work well.

Additionally if one bulb is not the same as the others on the same circuit will also turn the indicator on.

Haasman

Hmmmm; my '86 420 has this illuminated each time I turn on the lamps, until I hit the first bump. I have a tail lamp loose in the socket and it makes contact. Sort of amusing, I think, but I guess I'll try to rectify this.

With each and every used car I purchase, I check and almost always replace the the brake light, license plate and running light bulbs. Why? Because they are usually dull and yellowed.

Bright bulbs = good visual awareness, most especially in bad weather. Also, on a purely pyschological plane, to me, dull bulbs on a dirty car just seem to indicate something to me. Read into this any way you want, but a well taken care of car with clean paint, bright lights just makes a statement of confidence. Put it another way, which car would get pulled over?

Any way .....

..... A bunch of new OEM style bulbs do not cost very much money, only takes a few minutes to replace and also gives a good reason to check around each of the corners of the new car. I always seem to find something to fix or have learned about. Once you know how to get your bulbs out once, replacing a bulb in the future is often just a minute or two job. Nice when on a road trip with the family all loaded in.

Additionally, I will wipe out the sockets with a rag sprayed with
WD40 (conducts electricity) and often see if the sockets need tweaking to hold the bulbs tightly.

Haasman