Door Locks

Our 1999 Jetta gl has some lock issues. We lock the Jetta with the key fob and all the locks will lock except the driver side. It will not lock the door but the alarm will be set. If you open the door without disarming the alarm guess what happens! lol
I just need some advice on what to check to fix the problem.

alright i just got  a flip key made for my car and the dude who made the key said that if you take your driver door panel off there is a group of wires and in that group there should be a metal rod in the middle that turns when you turn the key in the door get some electronic cleaner and spray it. the wires corod of the years somtimes you need to replace the rod.

I'm having the same problem, when looking the doors with the key, all lock except the rear passenger door.  any luck saab man with this fix?  I plan on digging into this, this weekend...  will let you know how it works out.
 
Thanks for the help.

check that, and when you take it all apart, make sure everything in your locking mechanism is hooked up properly. good advice though!

I had this same problem! dont know about your jetta, but my locks ara on vacume lines, not rods. But my problem lied in the wire harness itself. When you open the door. Right inside the hinge, there should be this black rubber casing. If you peel that back you will see the entire harness you might wanna check to see if the wire is torn there. if it is you could just solder it back together. If not maybe isided the door behind the door panel. Also check the vacume line to see if its attatched all the way! Good luck