Originally Posted by onehundred80
I have a digital multimeter, but the diode I found to be at fault could be tested using a bulb and a battery.
Diodes only let the power through one way, I used the buzzer feature of the meter and found that power went through the good diode only one way, but the other diode did not let any power through in any direction. This indicated that no power was getting to the seat switch with the door closed.
If you can put your hand on the relay and open the door you can feel the relay 'click' as it opens, shutting the door you can feel the same click as the door shuts.
If you have good ears you can operate the door switch and hear the relay click.
The seats now operate with the doors open or closed, with the ignition on or off.
The Mercedes sites mention the fact that this relay may have dry solder joints that cause problems.
Thanks, mine went bad, I dont know why but the seats did not move at all. door opened or closed. The relay was hot , like it shorted out?. I ended up getting a new one for $15 dollars,now everything is back to normal.