I have a 91 240 with K on it. When I'm driving at night . My dash lights are very dim at idle.The idle seems to be low. When I hit the gas peddle. The dash lights get bright. I had the battery and alternator checked. They check out OK.The problem seems to be getting worse. Now some dash lights are coming on at idle.It hasn't stalled yet.It's just about to.Mygas filter is 2 years old and I only run 93 in the car.

Thanks

 

Mine did that this spring (also a '91). It was the alternator. I installed a rebuilt one and the problem went away.

 

If your dashboard has a dimmer switch for the lights then that might also cause the problem. Dimmer switches get finicky as they get old, and start getting sensitive to bumps and changes in voltage

 

The grounds are around the bottom screws for the center console. Maybe the screw is loose, i would check the grounds.

 

i have the same gremlin what fuse to check? .....
already cycled the dimmer switch..no change..

 

did some tests today..alternator putting out 14/14.3 v running with nothing on...drops to 13.5/13,8 with stuff on ..blower motor/lights etc...
so where to look next?

 

unfortunately nothing i did today helped much.. checked/cleaned all the grounds i could find and reach under the hood. grounded the alternator body
to the engine with a jumper wire. spun the fuses in the fuse box and even replaced a couple of 16amp ones. ebrake light is bright and steady
with KOEO. still getting the (slight) flicker only with engine on.... any other ideas out there?