ALWAYS HOT in the CAR

[stanski]

The heating controls do not work correctly. The normal temerature contol cable was replaced 6 mths ago by garage, who had replaced it with a "clip" some 9 months before this when the A/C control went wonky. Temperature knob would not stay in selected position.

Garage now wants £300uk for new part (not certain what this is), plus labour.

Does anyone have any suggestions what could be the problem, any cheaper repair ideas?

YARIS Verso 2000.

[CTScott]

The hot/cold knob simply moves a door (the Air Mix Damper Control) in the air box to adjust how much air blows over the heater core. In the picture below (which has the blower stack removed) you can see the Air Mix Damper Control cable, which is the lower one:

http://www.yarisworld.com/forums/attachment.php?attachmentid=33552&d=1272375666

With the engine off, if you put your head down below the dash and rotate the knob, you should hear the damper gear train clicking and when you reach either end you should hear a thump from the air box. If you don't then either the cable is not properly connected, the gear train (which is part of the air box side of the control cable) is broken, or the flapper door is jammed.