300E lamp bulb warning light intermittent problem / cruise control
 

Hi everyone!

I am having a problem with the exterior warning light indicator in the dash on my 86' 300E.

For the past six months or so the lamp failure indicator in the dash turns on and off intermittently when the headlights are switched on. On several occasions I have circled the outside of the car trying to locate the so-called burnt out bulb but cannot locate it- every bulb is lit!

Does anyone have any suggestions or been through similar experiences that might shed light on this situation?

Also, I have heard that sometimes surging cruise control has been connected to lamp failure. My cruise control will accel, but not maintain speed. I have checked all the rear bulbs (except the high-mount) to make sure they are silver based bulbs.

Thanks in advance for any help anyone can give on these problems. You are all great!

Jerry

When that problem surfaced on mine, the lamp indicator stayed on "solid" whenever the headlights were switched off, but went off when the headlights were on.:confused:

The system is a bit tricky to diagnose, but I'm inclined to believe that the problem lies with the metal rails embedded in the rear taillight housings. Sometimes they get loose over time, and lose contact with ground. So even if the lamps in the socket get juice, the resistance is enough to set the lamp indicator on.

Also, inspect each of the bulbs carefully. If the bulb is turning black, it's on it's way out, even if it still works. That can also change the resistance enough to set off the lamp indicator.

Since yours comes on when the headlight switch is on, concentrate on the bulbs in the rear taillights that come on when the switch is on. Press down on the metal rail near each of those bulb sockets and see if the lamp indicator goes off. If it does, try to crimp the rail down firmly to ensure good contact.

This solved my problem, until the following week when I backed into a truck with a lift kit, shattering the lens...so I just went ahead and bought the whole tailight, so the problem really was fixed!

I had a similar problem on my '95 E320 a couple of years ago.

I can't find the invoice for the work but I'm pretty sure it was described as a faulty brake light switch.

Hi,

Same problem on my 300E

All lights were working but one was on the way out -- warning light only came on when reverse was selected.

Changed reverse bulbs and brake bulbs while I was at it. problem solved.

chicago124

Thanks everyone for all the great suggestions!

I will check all the bulb fittings tonite and report back!

Jerry

300E lamp warning light
 

I had this problem with my 300E(1986). I found that the bulb clips on the tailights are often weak and jiggle out of their sockets. The actual light which was out in my case was the right side rear bulb on the side of the taillight lens. It looks ok until you compare it with the left side. Any object pressed against the tail light covers tends to cause the bulb to dislodge. I usually give it a tap and the inside dash warning light extinguishes. Hope that helps.

al

Thanks for everyones help with this silly stupid problem.

Now the warning light seems to be staying off... I checked to make sure that all bulb fitting were tight in the sockets.

The cruise control is still surging but at least the little annoying warning light is out.

We will see...

Thanks,
Jerry