Problem with Central Lock System drivers switch 85 4000Q

[MXHOWES at aol.com]

Re: 85 4000Q
My drivers door switch for the central lock system quit working  for 
opening the doors, it still works for locking them. I went to the pump  and it can 
be hot wired to work in both directions. There is no power  getting to the 
pump in the 'open' direction. My question (before I rip the  door panel off) 
: Is there any adjustment to this switch and a chance I can make  it work 
again or should I start looking around for a new part first? I have a  very 
old parts book that shows 443 959 855D 01 for that switch, can anybody  
confirm that #?