I believe I discovered a solution for the intermittent, defective operation of the door locks and window switches that used to come and go in my xk8 without explanation.

After learning about the weak solder terminal in the ABS computer, I decided to zero in on the locking and security module in the trunk hoping to discover a similar simple fix for several bizarre things that started happening to my car. The driver's window would not wind down sometimes, and other times would not wind up. The door locks would lock electronically sometimes and other times only the driver's side would unlock with the key. One morning I went out and noticed that the rear windows wound themselves down.

I finally removed the security and lock module from behind the battery in the trunk. You can see an antenna cable plugged into the front of it. I disconnected the antenna and other clips unbolting three bolts and pulled the unit out of it housing and out of the car. It was clean and dry with no frayed wires or connections.

I released the tabs around the edge that held it together and opened the two halves exposing a circuit board. I noticed that you can lift the circuit board out of the plastic case, but there is a small, thin four-wire flat cable that runs from the circuit board to another piece linked to the antenna plug.

I lifted part of a two piece white fixture that the cable connects to at each end to remove the tips of the cable and cleaned the tips of both ends before reattaching them into the white fitting on each component.

Before I did this the driver window sporadically would not roll up and the electronic locks would sporadically not operate. After I did this and reset the remote everything worked fine and has continued to work fine for the past week. I think I isolated and corrected this quirk, negating the need for a new module.

 

very interesting, and now it can be found by future members using a multitude of keywords. I suppose you didn't document with pictures, just in case it didn't fix it, no need to photograph it, right? Good, detailed description, nonetheless.

 

I too am having problems with my FOB and sometimes the passenger window. I will look into this. Thanks....