I had a similar problemw ith my passenger door, the pump was working, but the passenger door was not triggering the pump when using the key. it would lock when locking fromt he trunk and drivers door.

I pulled the seat, pulled out the pump and traced the wiring and found a break int he wire and repaired it. I also extended the plug wires and made sure they were seated properly in the socket on the pump.

There should be a harness with a white plug with a single white wire coming into it as well this is all part of the system.

You may need to pull the door lock out of the door, there is a wire that is attached to it that is clipped on tot he door lockw ith a plastic clip. that clip can break and cause it to not make contact, which could be related to the problem.

It could just be that your pump is bad, but I would start with checking the wiring, then if that is ok and the pump is getting power, start checking for a vacuum leak. my fuel door lock was leaking, so I simply plugged the vacuum outlet for it at the pump until I can remove that fuel door lock and try to find out what is wrong with it.

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon - Sold
2006 E350 Wagon - 368 - Dead
2015 GL350 Bluetec - 197U