Blinking switch lights
 

Here's a strange one. Lately, when my foot is on the brake, car in any gear but Park, the lights inside most (but not all) of the interior switches (e.g., window switches) start to blink on and off. This despite the fact that the headlight switch is OFF so those little light bulbs should not be getting any power. Obviously there's a short somewhere, sending power into the lighting circuit. Any ideas where to start? The fact it only happens in gear and with the brake on makes me suspicious about the brake/shifter interlock, though I believe M.B.Doc said this is a purely mechanical interlock.

Any thoughts would be appreciated!

May have low bat voltage..
Do the blinks stop if you give it a little gas????

You know, I'll have to check. Now that you mention it, it only happens at idle so that's a definite possibility.

Well, that didn't pan out, unfortunately. Engine speed doesn't seem to matter. Now happens regardless of shifter position.

The only constant is that it so far only happens when the brake is applied. I am still suspicious that that's a major clue. My brake/shifter interlock hasn't worked for a couple of years (i.e., it lets me shift out of park even if the brake is not applied) which makes me doubly suspicious there's some connection.

I took the wood cover off the center console to look around. The two grounding points look good and tight. No obvious shorts anywhere.

I would love to know how the shifter/brake interlock system works. I've looked in the MB CD ROMs and in my Haynes manual and I can't find any reference to this system. Anyone know how it works, and if there is some way for these two symptoms to be related?

I'm reactivating this thread to see if anyone might have any ideas on how a malfunctioning brake/shifter interlock might cause the lights on my interior switches to be energized (and blink) ...