1996 SL320 Electric AIR pump always on

New poster here, Patrick Opsahl in Santa Fe, NM.
Problem: Our 1996 SL320's AIR pump was on after we parked and exited the car? Sounded like the electric radiator fans were on, they were not on. Found the 2 wire electrical connection located on the front of the electric AIR pump (underneath the alternator, twords the radiator) and disconnected it, AIR pump stopped. Reconnected it and pump restarted.
I checked the archives and could not find this happening to anyone else? Did read that the AIR pump is only suppose to come on during start up? What if I do not reconnect it, what effects on engine performance? Online catalogs list it for $700.00! With that price I am willing to take it off and see if I can disassemble and locate the problem.
Any fixes or suggestion?

Also, I want to change the automatic transmission fluid and filter (722.507). Do I have to use MB fluid?

Patrick

Found the circuit for the elctric AIR pump. Fuse M4 and relay K17. Reseated the relay and now all is working correctly with the AIR pump?
I will order another relay just in case it happens again.

Patrick