Questions and Answers

Mercedes Benz 300E Eats A/C Relays Q. Hello, I have a 1987 Mercedes Benz 300E it has 99,046 miles. I'm having A/C problems. For some strange reason the A/C control relay burns out. I've replaced it and the A/C will work for about a week and then it stops. The car has been changed to R-134a. The mechanic can't seem to find the problem and every time I take it in, it works after they change the relay. Is there something the mechanic don't see? Would like to know your answer. Thanks, Roy

A. Anytime a relay burns out in this fashion, it usually means that too much current is being drawn through it. In this case the A/C compressor clutch may have a few windings shorted and thus is drawing more amperage.

This is easy enough to check for with an in-line ammeter.