Change or repair heater control unit,

Hi, I have done some searching but not found the answers yet

My son's TF has had heater control problems since we got it at the end of last year.

The control valve itself seems to work ok but the know didn't have too much affect on it

When I was playing around with it a few weeks ago. I managed to take the knob off, and when i pushed it back in, it pushed the shaft back in instead of pushing on to it.

This evening I decided to sort it, and managed to get the shaft back through by getting my hand in the passenger side of the console, and got the know fitted again

After operating it a few times, it went slack and I am not sure if the mech has fallen to bits or the cable snapped.

I have a spare F unit to play with so thought I would drop it out.

Are there any guides to doing this as it looks a complete mare.

My f heater controls have been serving me & all other previous owners since1998, when I had the tf the controls fell to pieces. It left my ownership with an early set of controls, read into that what you will.

There are various guides to stripping down the control unit! I found some useful ones on YouTube. I had similar problems when the c clip came off one of the control shafts causing iy to disappear when I tried to put the knob back on!