I need 12V (board voltage) on my left steering wheel.
I thought this would be child’s play as there are the wires for the clock. I opened the clock cover and found the cables.
I checked the fuse panel and clock fuses, everything was fine, but no voltage at the steering wheel. Unfortunately , I couldn’t figure out the cause. The wiring Diagram has no answer and all main switches were on. Is there someone who has experienced the same.
Thomas
The Wiring Diagram says it must be connected over fuses panel
I would open the whole yoke assembly and look for more wires. Then check the fuse.
So finally I figured out the wires for the clock are only for controlling the clock lighting. The voltage regulation of
9.7 to 0 volts takes place via the voltage controller RADIO LIGHT. No other cables found, a great pity! Unfortunately it wasn’t child’s play.
It is a bit fiddly but not that hard to run another wire through the yoke tube.
But no two TB20s have the same wiring anyway, ex factory 
