Loss of heater control - full hot air in cabin!

[J44EAG]

Following a post on the XK8 Bulletin Board, it is useful to have this topic repeated here.

S-types have a habit of loosing heater control typified by electric heater valve failure. Changing that valve located at the front end of the engine bay is not easy only perhaps to find that changing the valve has no effect.

It is therefore worth trying this quick and easy idea before condemning the heater valve itself.

Located just to the left of the steering wheel on the dash surround above the dimmer wheel unit for dash lighting, is a small rectangular slatted vent. Removal of the vent is simple using a small screwdriver or indeed a finger nail. Be prepared to be horrified. I found the area behind the vent chock full of dust, fluff and muck. Behind all that lot was hidden a hot wire and bulb temperature sensor not dissimilar to a MAF sensor in appearance.

All this grunge can be hoovered out or if care is taken, dislodged with a small paint brush and blown out with a length of rubber tube and lung power. Do not be tempted to use airline pressure or touch the hot wire and bulb with a hard implement such as a screw driver. The hot wire is extremely delicate.

I`ve just carried out this action on my ten year old S-type and am overjoyed to find heater control has now been fully returned having spent little more that a couple of minutes clearing out the crud. If only all repairs were this easy!

Thanks to Jeff 1954 for this great tip.

Mike

[Montana5]

Not surprised yours is dirty Mr K

Seriously though that is a useful tip, pictures of the vent and sensor can be seen on the last page of the DCCV & CCM fault diagnosis guide as posted in a previous AC thread.

[J44EAG]

Thanks for that, Doug.

Mike