I have a 1989 XJS. My lumbar is not working on both seats When i tress the switch in both sides i can heat the pump run. Neither side will not deflate oy inflate any ideas on the cause of this, Thanks

 

Run the seat all the way forward, and take off the back panel of the seat, very easy to do. Check the air lines and connections. Common for plastic lines to break, or rubber connections to fail. The problem should be obvious once the seat back is off.

 

So they're inflating only? Does the pump make a noise when deflating?
I had this, I think something (valve?) was stuck/gummed up from lack of use - I just held the deflate button down with the pump running and after 20 seconds or so it changed sound & started to work and deflate the bag.