Power windows operate thru a relay usually, under the dash, the power seat probably is wired into it also, I'd find it and either try a test one out of a junkyard first if you can find one...
p.s. Just for curiosity I did a search at Autozone, couldn't find a power window relay specifically. They list several relays, including power door locks and a multi purpose relay. You'll likely need a corvette detailed repair manual to go further...
