Been looking thru the manual & the only thing they recommend is to check the vacumn lines re: leaks. etc. Take the seat cushions out & see what you can see. I may be wrong , but apparently the bolsters are operated by a bladder & are released by a return spring?
My 95 manual speaks of the "bolster bladder". So I guess there is a bladder in each bolster that is operated by the air pump & returned to the open position by some kind of a return spring. Thje manual
is really lacking in this portion. No definitive diagrams of any of the hose routings, etc. If you find
a problem pls let us know.