The lumbar support adjustment is not working. Under the seat I found a loose and damaged circuit board without its plastic box. Seems I need a new or used circuit board and the plastic box. Which model years of XK 8 use the same Jaguar board as my 2003 model? Did Jaguar use the same board in other cars? Would be most grateful for any experience on this topic.

 

Which seat type do you have? The standard and Recaro option work differently.

Second question: do you hear any sort of motor running type of sound or nothing at all? The standard is an air bladder type support and it is possible that the pump runs debut it is the bladder that has developed a leak.

 

My seat is the standard one. No, the motor is not running when I push the button. The cushion is stuck in a position where it is completely full of air. All the other seat modification buttons work as expected.

 

You might want to GENTLY work the trim off and check/clean the circuit board where the buttons are. They can get dirty and exhibit poor contact. Folks have reported good success with simple alcohol on the contacts. Be double careful as that trim is, to my knowledge, no longer available. You might wat to look for pictures of the trim to find out where the tabs are to minimize the chance of breaking them off.

 

Thank you, Charlie! Problem solved. I wrongly thought there would be an object pushed up and down. After having read your explanation of how the lumbar support works I went out in the garage to test if I could hear air deflating the cushion when pressing the button for decreasing pressure. And there it was, a very gentle sound. The damaged seat control module had nothing to do with my experience of not controlling lumbar support. Now I only need a new plastic box for the control module and fasten it properly under the seat.

 

Glad you got it figured out and lucky you don't need to replace a bladder or the pump motor. It is a real pain to get at.