Solenoid motor comes on when starting and after turning off the engine. 2015 535

What is your question?

When I start the engine a solenoid motor comes on for 3 ish secs. Same thing when I turn the engine off. Sounds like it's coming from the back seat area. The auto trunk open/close works fine. The outside mirrors do not move when this happens. Are they supposed too?I turned off the passenger outside mirror that dips when backing up. I tried re setting the seats/mirrors several times but the solenoid still comes on. The outside mirror close option works fine. Except for this everything about the car is perfect. Has just 36K miles

What makes this problem better or worse?

nothing

How long has your 2015 BMW 535i had this problem?

A week