Missing Wire in Tail Lights Causing "Lamp Defective"?

[skateboarder]

I recently bought a 1996 E320 and I hope you guys can help me out with a problem. I frequently get the "Lamp Defective" message and figured out it was one of the rear lights on the passenger side (see pic below):



When I attempted to change the bulb, I noticed that there was no bulb in there at all! There was only a plastic cap covering the place where the bulb is supposed to be! So, I removed the plastic cap and put in a bulb (which I knew was good) but it still did not work.

I removed both the working and non-working lights to compare them and noticed that there are three wires in the working lights and only two wires in the non-working lights (see pics below):





Is there a wire missing in the non-working lights? If so, how can I fix this problem? The "Lamp Defective" message is getting annoying. Thanks in advance for any suggestions.

P.S. I do not have the owner's manual, but I am trying to order it.

[E-Klasse]

You are talking about the rear fog light. It will only work on the drivers side. The connector is there so that it can be installed in the UK on that side. Most people add the extra wire and bulb so that they both work but from the factory you will only have one installed. So that is not causing your problem.

Lamp defective alerts come from poor connections most of the time at the tail lamps. You can brush the contacts to remove oxidation and improve the conduction. I had a front fog light that was causing mine to display the fault from time to time. It had a crack in the lense that let a little water in when ever I would go through the car wash or drive through some water. The water was enough the change the resistance at the bulb socket. Once it dried out, the fault went away.

[skateboarder]

Damn, I feel silly now. I thought that light was defective but now I learn that it is supposed to be like that! Oh well.

So I did another search through the car for a defective light and I actually found it - it was an interior light, the one at the bottom of the rear door. I replaced it, so now I hope the "Lamp Defective" message will be gone. Thanks for the help.

[Mark Cummins]

Inspect the rear tail lamp bulb holders..They MELT and will cause the lamp to come on

[E-Klasse]

skateboarder - 9/13/2005 7:41 AM

Damn, I feel silly now. I thought that light was defective but now I learn that it is supposed to be like that! Oh well.

So I did another search through the car for a defective light and I actually found it - it was an interior light, the one at the bottom of the rear door. I replaced it, so now I hope the "Lamp Defective" message will be gone. Thanks for the help.

Stick to looking at main lights that are part of safe operation of the vehicle like headlights and taillights. Lights like the glove box light and the door lights are not used for vehicle operation. They are just courtesy lights. I would suspect the rear taillights as Mark mentioned.

[mjhawkins2346]

Some of the experts that have responded can give the exact particulars, but I was bedeviled by the "Lamp Defective" alert. My observations suggest that the computer is very sensitive to the overall circuit resistance or impedance. If it gets out of the expected, and tight range -- it generates the alert.

I changed bulbs ( to MBZ spec bulbs ) cleaned contacts with a contact points file and alcohol, as well as swapped carriers from side to side and the problem would go away for a day or two, and then come back.

I finally solved the problem with some di-electric grease on all the contacts - the bulb and the bulb holder. This grease keeps the contacts clean and at a stable electrical value. You can pick up a tube for $3 at an auto parts store.

Good luck.

[BENZDOC]

read this http://benzworld.org/forums/forums/thread-view.asp?tid=1175642&posts=22

[Rafael Grullón]

You can have both rear fog lights working if you connect the right side too. Get the socket, the bulb and a few feet of wire.