Just bought "babied" 1991 Mercedes 300E 4-matic and everything worked. Took it to get oil changed. Now door locks and air ortho seats do not work. Air pump not come on. Suggestions?


Asked by Sep 18, 2015 at 05:04 PM about the 1991 Mercedes-Benz 300-Class 4 Dr 300E 4MATIC AWD Sedan

Question type: Maintenance & Repair

Just bought a mint 1991 Mercedes 300E - everything worked until took for
oil change.  Now power locks and air operated orthopedic seats do not
work.  Air pump does not come on.  Could there be a connection between
this and anything they would do during oil change?  Any tricks, suggestions
without spending $300 to diagnose?  Just cannot hear air pump come on
at turn of key as usual.  Thanks

5 Answers


There should be no correlation, but who knows what happens when guys get under the hood- anything is possible- the timing is suspicious- just take it back to them and see if they knocked something loose-

1 out of 1 people think this is helpful.

By saying "no correlation" do you mean that there is no correlation between the air powered locks and the air powered ortho seats? Or are you saying no correlation with the oil change? I just thought that there may be a common failure of the air pump and/or its controls that happens with these models. Thanks for response

Mick Stewart

Take the air pan off the top of the engine and have a look for a loose or disconnected vacuum hose.


I doubt there is any relation between the oil change and the problems you are having.


Check the air pump fuse!

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