Wipers, fog light, windows, tail lights, blinkers all working intermittently

I have a 2002 Mercedes E320 station wagon. Today I walked out to the car and for some reason my tail lights were flashing. I started the car everything worked fine for a minute then after a few minutes of the wipers being on all of a sudden my front wiper stopped working and my rear wiper started going. Also after I stop and shut off the car the fog light would not turn off. Also the windows would not roll up and the horn did not work. Please help

We usually call it the Body Control Module.

But in your vehicle, it’s called the convenience/comfort control module.


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Tester’s hunch is a good one. But start with testing the battery and cleaning its connections. Many will advise a battery over 4 years old is on the downslide and should be replaced. A wiring diagram might disclose that all those circuits share a connection or a ground, and that would narrow it down. Don’t be surprised if it is that (probably expensive) module.

Was the car ever in a crash or a flood?

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No no cross recently. Just was having heavy rain when it started no flood. Internet says Sam module could be it but I want to be sure it’s that before I waste time replacing it

Then pay a shop to do an actual diagnostic .


The standard Battery/Charging system test is where I’d start, before considering any other possibilities. If that test doesn’t turn up the problem, short circuits in the wiring harness can sometimes cause light circuits to flash. That’s more likely if the flashing circuit is protected by a circuit breaker. Best method usually is to get a proper diagnosis before replacing parts.