The brake lights do not work. I discovered that the electric static noise is comming from the "Combination Relay", it the the 2nd largest there. The largest one is the "Exterior Lamp Failure Monitoring Unit". I exchanged the "Combination Relay" with the identical working one from my 1990 300D, and still get the same problem, while the one from the 87 works fine in the 90.

After touching the Relays, I discovered that Relay "A" as per electrical drawing, which is the "Power Seat Relay" was soooo hot to touch that I could not even touch it for 1 sec.

I am waiting for it to cool, and then I will pull it out and swap it. I don't think it is normal for a relay to heat up so much???