Contact one of three places that I know can get you a wiring harness quickly.
Performance By Design (913)962-4317
Ask for Tony
He's drop shipped Supra stuff to me in two to three days
Powerhouse Racing
www.powerhouseracing.com
I've done a lot of buisness with Jarrett he's a good guy but sometimes a little more expensive.
www.Suprastore.com
They get a lot of parts for Powerhouse and Powerhouse does a lot of work for them. They are all pretty good guys and pretty decently priced.
Hope that helps