Secondary night heater control switch.

[Rosie n' Jim]

I have a DL1C compact with a 701 timer controller. The 701 is in the rear of the van within easy reach of the bed, very handy on those chilly mornings. However, being an air cooled engine, the cab heating can sometimes not be enough. I'd like to be able to replicate the on/off button of the controller on the dash. 
Easiest would be to feed power to the (yellow?) Wire that starts the heater running, but not sure if this would work with a controller connected,  or what the heat setting would do.
Alternative would be to solder extended wires from the swith o  the controller board.
Any advice would be much appreciated. 

[Oldiebut goodie]

Search is your friend.
https://club8090.co.uk/forum/viewtopic.php?f=39&t=95419&start=0&hilit=one+last+eber

[Rosie n' Jim]

Many thanks. I did a Google search which bought up lots of hits but didn't see one from 80-90. Probably poor choice of search words.
Hopefully this won't be needed for a good few months!