Since my plan with the waste gate controller is to install it behind the shifter where the TEMS controller now resides, I needed to relocate TEMS box.  My Supra had an open switch spot on the dash (coin slot) and I decided to see if I could put the TEMS there.
 

The current TEMS switch is a simple on-off device with three wires- 12 volts in, out to the TEMS ECU, and ground.  Pushing one button closes a contact and sends 12 volts to the TEMS ECU for sport, pushing the other opens the contact and the TEMS is normal.  I bought a fog light switch from a junkyard for $5.00.  I moved the TEMS wiring harness from the center console up to the left side of the dash, removed the old connector, and soldered on the fog light one using only the two switched leads for the TEMS.  I then spliced the other two switch leads into the dash lights.  I cleared and repainted the lighted part of the switch using a little piece of rectangular tape.

None if one is familiar with a soldering iron.

1- First flaw: the color of paint I used is too silver and I need more of a metal flake charcoal.
2- Second flaw: the opening I made for the light is in the center and needs to be to the left as are the stock switches.

This was a simple mod and paid off well for me.  As I only needed this mod for the waste gate controller install, it probably is unnecessary for most.