you should look from the front of your seats to see if all four vacuum elements (there are two in each seat) are connected to the main line (there's only one).

The main line (if I remember correctly) ... comes into the interior from the driver's side?

I'm not sure of the color I have to check...
I'll look at it and update you guys on this.

One of mine was leaking so I plugged that element and the seat still locked with one element. I need to fix that..

Yes they are connected somehow.......

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2008 BMW 335i Coupe