I recently switched out my Disco S model vinyl front seats for some leather ones with the seat heaters and installed the switchs (now I have a nice warm butt!). There isn't much of a resale market for the vinyl seats and mine were torn so I decided to pull out the motors and harness in case I could use them. In the upper squab on the outer edge under the foam rubber I found what appear to be some kind of pump with a wire harness and it is attached to a hose and a small clear vinyl bag that is stapled to the seat mesh support in the area of your lower back (lumbar) and appears to have some air in it. It looks like it can be filled or deflated.

Since I have the cheapo model Disco for that year, do the upper models come with some way of changing the feel of the lumbar support area and assuming my leather seats have it can I add a switch or something?

Here is what it looks like

 

Check your seat control and see if the forward back switch is a 4 way or not, if so it should be wired and a wire harness should be under the carpet.

 

Cool, my truck has it, learn something new every day. You inflate/deflate it by moving the back adjustment **** up or down.

 

If it works, some of the bag's tension screen get worn out and they inflate backwards or inflate and then do not deflate at all.