[lowrydr310]

This is on my 2006 330i. I can't adjust the drivers seat forward or backwards when I'm sitting in it. I can hear a click when I press the switch forward or backward, just no seat movement. I can move the seat as long as I'm not sitting in it. Once it sit in it, the seat won't move.

I confirmed there are no obstructions in the track. Does this sound like a seat motor that's failing?

[NZE90]

Yes it does sound like the motor. I had this happen to my 08 325i. I removed the motor and opened it up. The brushes were completely worn out.

[lowrydr310]

I'm confused why it won't move with me sitting in it. If I lift my weight off the seat bottom cushion and press my back against the back rest I can still slide the entire seat forward easily overcoming the resistance of the weight. As soon as I sit down on the base there's no movement just clicks. This makes me think there's some lockout or sensor malfunction elsewhere. I guess it's time to see if there are any codes.

[NZE90]

Originally Posted by lowrydr310

I'm confused why it won't move with me sitting in it. If I lift my weight off the seat bottom cushion and press my back against the back rest I can still slide the entire seat forward easily overcoming the resistance of the weight. As soon as I sit down on the base there's no movement just clicks. This makes me think there's some lockout or sensor malfunction elsewhere. I guess it's time to see if there are any codes.

That's what electric motors generally do when the brushes are worn. They will work when there is no load on the motor but if you load the motor up they won't as the poor contact from the worn brushes will not allow sufficient current flow. Electric motors need more current to operate when under load.

[lowrydr310]

Originally Posted by NZE90

That's what electric motors generally do when the brushes are worn. They will work when there is no load on the motor but if you load the motor up they won't as the poor contact from the worn brushes will not allow sufficient current flow. Electric motors need more current to operate when under load.

Yeah I'm familiar with worn brushes but this is weird behavior. I am loading up the motor and it works just fine. If I lift off the seat but press my back into the seat back, the motor can easily overcome this force and it can move the entire seat forward against my weight (with me aggressively pushing against the floor with my feet and pressing my back into the seat) without any problem.

If I sit down in the seat (far less force required for the motor than me aggressively resisting or helping its movement) it won't move, I just hear the switch click. If I lightly lift my weight off the seat it moves fine.

This seems more like it's sensor related however there's NO driver occupancy sensor. I'll scan for codes, but I'll likely pick up a spare seat motor from the junk yard.

[Ohio Enthusiast]

Perhaps there is some mechanical binding in the rails or screws that only occurs when there is weight on the seat cushion but does not occur with force on the backrest of the seat?