What is the procedure for replacing the engine control module on 92 500SL? The Mercedes mechanic(?) says he is 95% certain my problem is a faulty ECU. Problem is he wants me to purchase a new part from MB dealer for around $2700 and would not consider a used part even though based on a guess. I decided to try a used warrantied part and gamble on a $500 part vs his $2700 part and install it myself. Now I need help with details of installing the ECU. It is my understanding, after installing the ECU, the battery must be disconnected for 1.5 to 2 minutes then reconnected after turning ignition to on position. Does anyone know proper method of installing the ECU? Appreciate any info.