1992 400SE Electrical problem
 

Sometimes the dashboard warning lights flash on briefly when the windshield wipers are turned on in a heavy rain.

What might be the cause for this?

harness most likely... Lots of moisture and odd electrical happenings are some of the first signs..

How many miles on her?

Jonathan

It's a car I've considered bidding on which has 159K miles on it.

10 to 1 it has corrosion in the wiper relay harness connector. Will probably need a new relay and the corrosion cleaned from the harness.

The instrument cluster sounds like it is in need a Beckman fix. Very common on 140 body cars.

http://www.beckmanntechnologies.com/catalog/IconWebPage.asp?CategoryText1=Electrical%20Equipment%20%26%20Instruments&CategoryText2=Instrument%20 Clusters&CategoryText3=140%20Chassis

fasthair

Hmm. Looks like you are getting a lot of "possible" problems. It might be cheaper to take it to a local independent Mercedes repair shop to get them to check it before replacing a bunch of parts that are not the culprit.

That cluster alone looks to be about $600. :surprised