stingray6367

Please help. I have a 1992 400e. The accessories lights stay on all the time. I checked the fuses. all appears to be okay. I have turned the light switch in all positions with no change. Has anyone else had a problem with this? Thank you

Plutoe

Did you ever stop to think that the switch itself may be kaput!!

stingray6367

I have. Thank you for the reply.

stingray6367

I replaced the headlight switch with no success. It did not turn off the center console lights. Any other suggestions would be great. Thank you.

killme613

I have the same "problem" on my '88 300CE and I'm starting to think of 2 things. Either this is normal or the previous owner messed the wires around and connected the lights directly.

Floobydust

There is an analog buffer amplifier (behind the instrument cluster) in the back light circuit that essentially amplifies the variable voltage supplied by the back light rheostat in order to supply the current necessary to drive the majority of the back lights (console, gear selector, switches, etc.) This module is supplied with battery (e.g., not switched) current via Fuse 9, so if it fails shorted, the back lights will stay on. Remove Fuse 9. If the back lights go out, this is very likely to be your problem.

killme613

Thanks for the info, I had no ideea this is how the system is built. I just thought that the back lights were directly connected to the lights switch.
Will have a look this week and post results.