Thanks and reference to this link with a few fool proof wiring additions that work on mine.
http://homepage.ntlworld.com/mallwood/t ... ontrol.htm
Locate the red/black in the footwell connector (blue top)- the feed in to the connector on underside. There is no wire or terminal on the output side socket, Number 30 (numbered on the underside when removed.)
Connect a suitable guage wire from this to the VX TC switch number 2.
Connect from VX TC switch number 3 to ground. Or use heated seat Brown.
Illumination to VX TC switch number 4 taken from heated seat, Grey/Yellow.
The other unrelated VX switches heated rear screen, aircon, etc use a different number to earth.
This will when engine started enable TC. Press the switch and the instrument light will come on, meaning TC is off.
Hope this clarifies any ambiguity and where to put the wiring on the last of the Vectra B SRI 150.