Hi gang,

So I recently threw a used PSE pump into my S500 and everything works. HOWEVER, the passenger side rear door will only lock. When unlocking it stops about half way and won't fully unlock. If I BARELY lift with my fingers while unlocking then it'll go all the way.

What might be the best place to start looking? Soft close works, trunk works, lumbar etc.

Thank you for any advice. It's the side of the car my baby sits in his car seat, so the door gets used a lot.
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Maybe a leaking air line to that door lock

 

The door locking/unlocking systme share an air network. There is a leak somewhere. One is negative pressure, the other positive pressure. I'm not sure which is which, but leaks will affect one before the other (seems unlocking might be negative pressure?). Anyway, you have a leak and have to find it.

 

You might also try lubricating the latching/locking mechanism - while you are at it, do all four doors, the trunk and the hood.

 

Thank you for the thorough reply. I figured this much that an air leak was my issue.

I figured checking at the PSE pump is the easiest place to start as far as accessibility. For the door do I have to remove the entire door card? Also, what diagnostic process do I do to find the air leak? Soapy water?

 

Yes, lubrication helps tremendously in a weakened air flow that is barely strong enough to pressurize at all. A bit off topic but while you're lubricating, it doesn't hurt to clean the sunroof track and lubricate it as well.

 

for example

)for me) in my low to mid level amazon scanner it can do the pse test and clearly tells me my trunk circuit is leaking air