air con temperature control

[Roger695]

The air con in my 2005 Coupe will not control temperature. When the ignition is turned on, the unit beeps for 30 secs and shows a code 'er'. Then the set temperature is displayed, but the unit delivers either full hot or full cold, seemingly at random. Seems like the unit has lost the car temperature measurement.
Has anyone any suggestions, please.
Should I take the car to a Jaguar garage or an independent, or would I be better advised to find an auto aircon specialist?

[andypryce]

I would say it needs a diagnostic check, local independent probably the best bet.

andy

[mike020150]

A Jaguar independent equipped with either JDS or the Autologic Jaguar modules might be better (quicker) at diagnosing the issue due to the integrated nature of the XK8's electrical system. The initial error code reading could be caused by any one or more of a multitude of malfunctions. Earlier Jaguars had climate control systems which were easier to interrogate but they were generally less reliable. That's progress! Mike.

[jeff1954]

On the S Type there is a small vent on the dash just left of the steering wheel.
The front of this flicks off exposing a temp senser. This can be cleaned using a vacume cleaner. But I dont know if the XK has this .
If it has give it a try.

Jeff

[mike020150]

The XK8 does have the same arrangement and it's easily cleaned as long as you're not too hamfisted. However, dirty sensors are likely to result in slow responses from the climate control system. An error message tends to indicate a component failure. Mike.

[J44EAG]

Jeff,

You are Star!

I`ve had this problem on my S-type for a while now. Sudden full on hot in the cabin and a complete loss of heater control. I took to switching the whole system off, opening the sunroof and windows just to get some ventilation!!

As you said, the vent grill in the dash just pops out. The area behind the vent was chock solid with dust, fluff and muck. I cleaned out using a small paint bush and blew the whole lot out with a length of rubber tube and lung power. I now have a grey face!!!

The sensor unit found behind all the muck is not dissimilar to the hot wire and bulb arrangement found in a MAF sensor. Gentle tickling with the small paint brush removed all the accumulated filth. I replaced the small vent grill and warmed the car up to hot. Instant joy and happiness. I now have full heater control again.

Thanks also to Mike re fault codes and diagnosis. The fact that nothing in the heater circuitry was broken didn`t therefore show us as a fault code when I diagnosed the car via the OBD11 system.

Thanks guys. You saved me a fortune by not having to take the car to a specialist for help. I`d scratched by head about this issue for quite a while and couldn`t find out where the internal sensor was located or what my next progress steps might be.

If only all faults were this easy to fix. Just a question of knowing what and where to look.

JEC Forums definitely rule ok.

Mike K

[Nik]

Jeff,

You are Star!

I`ve had this problem on my S-type for a while now. Sudden full on hot in the cabin and a complete loss of heater control. I took to switching the whole system off, opening the sunroof and windows just to get some ventilation!!

As you said, the vent grill in the dash just pops out. The area behind the vent was chock solid with dust, fluff and muck. I cleaned out using a small paint bush and blew the whole lot out with a length of rubber tube and lung power. I now have a grey face!!!



If only all faults were this easy to fix. Just a question of knowing what and where to look.

JEC Forums definitely rule ok.

Mike K

Thats probably the problem I've had on occasions with mine Mike
I sense a little cleaning exercise coming on tomorrow

All the best mate ,

Nik

PS I should be coming down South shortly , perhaps we can catch up over a drink or two