How to fix CLK 320 LAMP Defective warning ??
 

I have a 1998 CLK 320 and the Lamp defective warning is showing. I have checked all bulbs and none of them are out. Is there something I can do or check before I take it to the dealer??

this also happened to me but , you need to check the lights more carefully. check the lic. plate bulbs and side marker lights. it s probably a bulb you are overlooking.

Did you replace the bulbs with bulbs from a autozone or car store ? if so that is your problem. Mercedes are tempermental when it comes to bulbs it has to be the right ohm and rating go to the benz dealer and purchase new bulbs for about $50 you can get all the bulbs you need for the vehicle i promise once you replace them with the benz bulbs the warning would stop ..that happen to me this past weekend and that was the remedy

I agree that you might be overlooking a inop bulb. Be sure to also check the center stop light, the small side markers on the rear tail lights, and the clear front/center running lights. EDIT oh and the fog lights

i've found that the LAMP MALFUNCTION alert is quite reliable. so if someone
says they checked everything, they usually (still) missed a bulb. only exterior
bulbs are part of the monitoring system. for my 99 E320 they are:

(2) H6W dim bulbs inside the high beam reflector,
(2) front bumper side clearance bulbs,
(2) dual filament bulbs on the outside edge of the tails
(2) single filament bulbs on the inside edge of the outer tails

...then, when you step on the brake,
(2) second of the dual filaments light up on the outside edge of the tails
(1) light array in the high-third-Dole brake light near center back window

....don't neglect to eyeball,
(2) lights above the rear license plate
(2) lights when shifted into REVERSE
(1) rear fog light on left rear, when headlight rotary switch pulled 2 clicks
(2) front fog lights in front,when rotary switch pulled 1 click

....and natch,
(2) low beam
(2) high beam

Also, on older models the bulb socket contact points get a little corroded and it changes the resistance. That's enough to trigger the error. The bulb will test OK but it's the socket. The sockets twist into place. Sometimes twisting all the way then rotating back slightly will provide a new contact point and all will be well. :)

You can do some tests to try to isolate the problem light. If the error appears when pressing the brake pedal it's one of the brake lights but won't go off until the engine is turned off. If it comes on when using the turn signals it's one of those. If it comes on when switching on the low beams... okay you get the idea.

Going to add in one light failure that had me miffed - LED turn signals in the mirrors. If a few of the LED's fail it will cause the warning light to activate but light on mirror (appears) to be working until you take a close inspection.

On this guys 98 he wouldn't have an LED third stoplight or any lights at all in the outside rearview mirrors.

The car in question has probably had three or four owners since the original post was made. :D

Good catch :thumbsup: