Heater control problem

[TVRPierre]

I have had the car since just before Christmas.

I knew the heater fan knob did not feel right and it certainly didn't seem to work right.
The heater blower is on all of the time and pressing the fan switch in increased the speed but turning the knob made no difference at all.

I took the dashboard top off today and checked the switch out. Basically the grub screw was not tight enough. Switch sorted.
I also noticed that the yellow wire connection has at some time over heated and someone has cut off some of the plug that had the black and yellow wires in it. Both of these were really loose connections so I have tightened them up.
I connected everything back up - the fan is on as soon as I turn the ignition on but now when I operate the fan switch the fan goes faster but it is variable by turning the knob.

A few things - I take it the fan should not be on all of the time, if so what is the likely problem and is it possible to get a replacement plastic bit for the connector?

Thanks
Pete

[rickprice]

The yellow and black connectors at the heater control unit are known to fail with time - the yellow more commonly than the black. Both have failed in mine.

They can be bypassed and soldered directly onto the connectors inside the control box. This is very easy and simple to do, and will prevent the unit failing in the future.

In terms of on-off, this should be controlled at the switch. I have a 2000 Chimaera and the switch pushes for on/off, and twists for speed.

Firstly you might check that the ribbon cable is not twisted and that '1' is lined up correctly at both the switch and control boxes. I think I had this when I was messing around with mine and I think it meant the fans were on permanently - but I can't be sure, I'm getting old and my memory fails me. But check this first.

I would have thought that if you truly cannot turn it off, and its wired up correctly, you probably need to source another switch - or at least borrow one to test.

Rich