Hi,
From some research I did on the web...

Spend some time with the car on and messing with all settings/buttons on the climate control system. If it constantly blows out the defrost vents on all settings--as mine does--that means the air distribution pod things are faulty. To actually get it fixed would be a LOT of money (dash must come out, and the parts ain't cheap--I've heard it's an all-day job at MB tech wages). For now I'm driving mine as is, since both the A/C and heater works (albeit, the A/C isn't as cold as I'd like).

When you turn the ignition on, ALL "idiot" lights should light up. If one doesn't--such as the SRS or ABS--it might indicate that particular system is faulty.

Check all the windows if they're electric. Two of mine were bad when I bought it, and a 3rd one went bad in the first month of owning--only one was the switch, the other two were the regulator/motor ($).

I think you're right, I believe it was '92 or so when the biodegradeable wiring harness issue came into play, but someone more knowledgeable than me might chime in.

Good luck to you, hope it works out for you!

I would post a pic of mine, but since I already did so in another post, it won't let me (that's pretty lame by the way...).