I have been suffering for a while with a heater system that will never fully shut off, so even though the knob was turned fully into the blue I was still getting warm air. This wasn't good on a warm rainy day with the hood up.
So I decided to have a fiddle a couple of days ago and see if I could adjust the cables.
This will work for either the hot/cold or the directional knob (winscreen/feet etc) as they are bothe cable operated.
First of all you need to take the footwell light panel off.
Drivers side for the temp and passenger side for the direction/vents.
First remove the 2 crosshead screws holding the panel in place.
And pull the panel forwards and down.
And disconnect the 2 spade connectors to the lamp holder. Remember which way around they were connected.
The heater control cable is the red cable shown here and the clip you need to play with is circled in yellow.
The first thing I noticed was that a loom was very close to the moving parts of the valve.
So I tucked the cable out of the way to prevent damage.
You can see the clip that secures the cable in place. The clip is just a spring clip that bites into the cable outer and holds it in place. You need to push the rounded tab away from you and towards the cable.
This releases the clip and allows you to move the cable up or down.
You need to move the cable up if you want more hot (A) or down if you want cooler (B).
I needed to move mine down.
Once adjusted you need to feed the rounded tab back through the bracket and push it until it clicks into place and bites into the cable.
The valve should now close more in my case when the knob is turned to blue. If the knob won't turn to the full cold position then you have adjusted too much
and you shoud readjust the cable until it is right.
So, know I have cool air once again. Err....Cool.
Remember not to place too much stress on the valve as it could easily be damaged. It is also possible that the symptoms are of a damaged valve and if this adjustment doen't work then you might have to change the valve.
The cable that controls the vent selection is on the passenger side and is coloured grey. The clip is similar.