My 300E was working great until I got the oil changed. Now my power locks and air operated orthopedic seats don't work. The air pump doesn’t come on either. Do you think there is a connection between the oil change and these problems that just arose? I can’t hear the air pump come on when I turn the key as usual. What do you think happened? How can I fix these problems?
Both of these systems are controlled by fuse 'A' in the electrical center of your 1990 Mercedes-Benz 300E. If this fuse is blown it would prevent both the locking and orthopedic seats from functioning. I doubt it was related to the oil change - this was most likely coincidental. But if replacing the fuse does not fix the issue, then you may have a direct short to ground somewhere so the wiring would need to be traced. If this becomes the case, you may want to enlist the help of a mechanic, such as one from YourMechanic, who can diagnose and restore your power locks and seats.
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