The grey wire is connected to a permanent live via fuse 37 in the hardwired fusebox, supplying both the Telestart and the timer,
The black is connected to chassis earth, and both the Telestart and timer and is connected to one side of the pull in coil, and one switched side of the FBH relay, a normally open relay contact, the other side being connected to pin three of the FBH.
The yellow is looped through to the cubby box timer, and is a signal wire from the Telestart unit to the timer.
Finally the purple wire is the output from the timer and Telestart, this goes high when the timer is active, the flame button override pressed, or the Telestart operated, and is connected to the other side of the pull in coil of the FBH relay.
I'll include a couple of keywords for anyone searching in the future, for Telestart T80 wiring Webasto parking heater timer wiring, FBH wiring.
Brian
