Battery Drain Problem

I need help! My daughter's 1987 190E (she's at college) has developed a weird electrical problem. When the ignition is switched off and the key is out of the ignition the instrument warning lights stay on, and the radio will come on if you try to power it up (which normally can't be done). The power windows also work with the key off. Needless to say the battery is being drained very quickly I had her pull the fuses for the power windows, the instrument cluster and the radio but they still worked! I need some advice on where to go with this. If anyone can give me some pointers I can drive there tomorrow to try to fix this mess.

[Robby Ackerman]

I'm just guessing ... perhaps there is a problem with the ignition switch. Does it have a wire feeding into it that is always hot?

My wife's turbodiesel years ago developed an electrical drain that would drain the battery every 10 to 14 days. I removed half the fuses, no change. Half the remaining, no change; all, no change. I bought a solar battery charger that plugs into the cigar lighter. That fixed it.

[Mike Richards]

Ditto Robby

Sounds like a faulty ignition switch. I suspect the battery ground strap will need to be pulled after each use in order to keep the battery from being sucked dry. I know that may be easier said than done under the circumstances.

OK, that's two replies that indicate a likely problem with the ignition switch. Is replacing the switch difficult and can you recommend a place to buy one? I have a Mercedes dealer nearby.

[Mike Richards]

I believe the basic idea is conveyed in the following thread. Check out what Benzmac had to say:

http://www.peachparts.com/shopforum/showthread.php?threadid=18442&highlight=ignition+switch

You may also want to try the SEARCH facility.