I have a '95 SL500 and there are three harnesses. The main or upper engine harness, the lower harness which includes oil sender and alternator, connects the starter circuit and a few other locations under the car and than the ETA. I have done upper and about to change the lower but I am waiting for the weather in Cleveland Ohio to improve so I can drive the car to a gas station that rents out their hydraulic lift. I tried twice now to replace the lower harness but gave up because I didn't have enough head room lying on my back under the car to navigate the very end wire harness ground connections around the back of the motor/trans. Much easier to do standing up under the car. Your vehicle should be about the same, Good Luck, Steve