Part number and price for a new adjuster assembly: 89041536 - $442.00.
Part number and price for a new frame (this may not be necessary, not sure): 10388123 - $75.10
Price for a new wiring harness: approx. $800.00-$900.00; depends on the other option on your vehicle. (There are about 10 different body harnesses for the H3, all dependent upon option content.)
Comfort for your Butt: Priceless
Prices do not include seat heaters which would be extra. In addition, price does not incude outer trim where the switch(es) are installed or the lumbar air pump, which would not be required unless you added in the bladders too.
You could, use a homemade wiring harness and save the big bucks for the new harness. This would be a completely independent system that simply controls the location of the seat adjuster; thus the seat itself.
You could wait for a while, and check junk yards, there are bound to be some wrecked H3s; especially in large metro areas.
In addition, for clarification purposes only, the seats, lumbar or heaters are not on the class 2 data link bus. Only components on the class 2 are:
BCM - Body control module
EBCM - electronic brake control module
SDM - inflatable restraint sensing and diagnostic module
IPC - instrument panel cluster
PCM - powertrain control module
Radio
RSE - rear seat entertainment
TCCM - The transfer case shift control module
VCIM - vehicle communication interface module (OnStar®)