'91 190E 2.3 door locks

[sbourg]

The way our vacuum door locks function is via any outside lock or the driver's door button. Specifically the front passenger door button does not do it. Is this correct?

Now, last night I was examining the 'vacuum pump' under the rear seat, and with the right rear door open, I could activate it by moving the button on the front passenger door. What gives?

The reason for examining the pump is in preparation for installing a keyless entry/alarm. It did not function the way I expected based on posts I searched. It has one accessible port, and provides either a positive or negative air pressure (rel. to atm.) there depending on the connection of the trigger wire. It also has a built-in pressure/flow switch which stops the pump in either mode if I block the port. I feel pretty confident that the keyless entry will work correctly, but would still like to understand the logic of the trigger system - or if it is functioning incorrectly.

Thanks for any input.

Steve