All's you need now is a wire from the switch to the fuse box and a ground.There are 2 elements,one for the lower back and one for the butt.See if you can get a post '86 parking brake console,they have the switches built in(easier than going up thru the dash).There is a dedicated fuse already in your box for heated seats.
If you had grabbed all the wiring from the switch at the junkyard,it would include the ground wire and fuse wire.
When you open up your seat to add the element use cable ties to close it back up instead of those hog rings.
Good luck,Phil
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philvo