Does anyone know what signals the pneumatic system to close the trunk snug? I've removed and examined all the pieces and can't see what does it. There is one contact switch, but that does not change its output regardless of whether the latch is in detent or fully closed, so it just appears to tell the computer that the trunk is not open, rather than tell the pump to activate.

This is driving me crazy.

 

I think it's time-based. When the pump gets the signal that the lid has contacted, it continues to apply vacuum for a preset interval to insure a seal. I think the interval is adjustable with a mechanical adjustment in the pump.

 

But how does the pump get any signal in the first place?