Heater Controls ??????

Hi
Just wondered if any of you have stripped a defender heater box. My heater works fine...well when I say fine it blows out the normal warm air. My problem is that when I pull the levers to adjust the motor speed or flap settings they will not return later when you then push them the other way. At the moment I have them set on hot and directed at the screen. Is there meant to be some sort of return spring behind the arms on the heater box or is it the rigidity of the sheath that is meant to aid the return.
Many thanks in advance.

Hi,i have had this happen to my 90, i managed to cure it by spraying white grease down the cable sleeving and then working the levers slowly up and down till they freed up.Took a bit of time but its never happened again and that was 6years ago.

cheers. I will give it a go