My 99 XJ has a couple of finicky wiring issues in regards to the power door locks and windows. The most recent of which had me so pissed off today that I finally had to walk away. I was fixing a broken window assembly using the old cotter pin trick, but after putting the driver's side door back together, I discovered my power lock will not lock properly. Here are the symptoms:

Unlocks all the time.
Locks when key is not in ignition.
Doesn't lock when key is in ignition and engaged, UNTIL door is closed.
Once door is closed and key is engaged, door locks properly.

Is this a grounding issue? Does it sound like a loose connection? Where would be the best place to start looking? Please help me before I loose my sanity.

Thanks.

Might it be a safety issue to keep you from locking your keys in the car?

Though the safety feature sounds like a possibility, I don't think that is the case. This is the first time it has ever happened which leads me to believe it is an electrical issue.

Thanks for the response. Any other ideas?

Nothing comes to mind....however I'm not the best person with electrical systems.

Fred is right..it keeps you from locking vehicle when it is running.
Took me awhile to figure out one time also. I was working on it too with key on and door open.