To my knowledge it pipes into the ODBII connector harness. I could be totally wrong on that though. I never knew our cars had TPS to gripe about the tire pressure. At least my 99GTP doesn't I'm pretty sure my 2000 GTP doesn't either.
Have you looked at any schematics? I have a membership with AllDataDiy.com it's like 12 bux a year or something. Totally worth it when you are trying to track something down.
http://www.alldatadiy.com/
If you google coupon codes you rarely have to pay full price for this site and it has a ton of knowledge on how to fix things in our cars the "GM" way.
