The Honeybourne hardtop is now on the car. Have spent more time getting the interior lighting to work. Because all the lighting that can be dimmed did not work I started at the lighting rheostat. All seemed OK there so followed the wiring onto the cigar lighter to find that it was not earthed. When an earth was fitted to the cigar lighter most of the heater control lighting started to work. Took the bulbs out and cleaner up the connections - now have all 4 heater lights working.
Then traced the wiring to the switch panel above.
|Triumph TR7 Heated rear window switch|
.PS On taking the dash top off I was able to retrieve the wiring for the heated rear (demister) window switch. The wiring loom included the wiring for a demister despite my car being a convertible. At the rear of the interior I was also able to find the ready fitted demister wiring.