Octavia Elegance TDI PD - 2 litre diesel, June 2008, about 103,000 miles. External air temperature display sometimes shows correct temperature , and sometimes drifts downwards, wavering between +15 degrees and -35 degrees. Fault started about last November (i.e. 2015) Sensor has been replaced - to no effect. I've noted that during cold weather the cabin sometimes gets quite hot despite the climatronic system - then adjusts to normal afer a minute or so. Climatronic controls look like this:
http://s264.photobucket.com/user/mark_eire/media/04082009268.jpg.html Since the warm weather (from early May) the a/c has been intermittent. This intermittency doesn't relate to the external air temparature sensor - sometimes it works when the external air is indicated at minus 25 degrees. But I've not noticed it fail when the external air is indicated at the expected temperature (generally 15 to 20 degrees). Local independent garage investigated: refrigerant half missing, showed 195 grams when there should have been 525 grams; so refilled it to correct amount. But a/c is still intermittent. Garage confims that refrigerant is still present with correct quantity, pressure switch is OK, fuses are ok. But when intermittent fault is present there is only 4.2v on connector to compressor. All the other fans and vents operate as expected. Compressor operates correctly if fed 12v from the battery. Another friendly garage printed out the relevant circuit diagram from Autodata. This shows an "AC/heater air intake temperature sensor". Is it likely that this is intermittently faulty? It would explain the strange cabin temperature changes in cold weather. Where is this sensor? How would I test it? Is the control module faulty? How would I test it? Is there any association between the external air temperature sensor and the climatronic system? The circuit diagram would suggest not but Autodata evidently does not have a schematic for the external air temperature sensor. It does seem to be a suspicious coincidence!
Is there a Skoda aircon expert in the Thetford area?
TIA
