Hi,

I have tried to read through every post on this subject, and there are loads so if i've missed the answer i apologise now!

My 53 plate L&K 1.9Tdi Octy has an issue where the ambient temperature is displaying (on dash & climatronic) -5 degrees c when the ambient temp is really about 10 degrees C.

The ambient temp sensor was replaced by Skoda but failed to make any difference, so I have a couple of questions that hopefully someone can answer.

1. How or which component receives and translates the signal from the ambient sensor?

The reason I would like to fix this is because the Aircon pump doesn't run, the previous owner had the system regassed but that didn't solve the problem and I want to eliminate the temperature sensor from preventing the Aircon from working due to its perceived low ambient temperature.

If it helps i have had the car plugged into VAG-COM and there are no faults logged on the climatronic unit:

Address 08: Auto HVAC Labels: 1Ux-907-044.lbl

Part No: 1U1 907 044 A

Component: CLIMATRONIC C 2.0.0

Coding: 11000

Shop #: WSC 31480

No fault code found.

Many thanks for any and all help with this, all suggestions are welcome:)

I believe the ambient temp sensor just feeds the dash display and air con controller - engine management duties regarding air temperature (or density, really) are covered by the MAF and the coolant temp sensor in the case of the glowplugs.

I'd check the connections in case the garage didn't fit the new sensor correctly. Otherwise, try disconnecting the sensor completely and/or replacing it with a resistor to see if that affects the dash reading...

I thought the Octy 1 had 2 ambiant temp sensors. One in the LH front near the horn and air intake, which fed the trip computer and engine, and one in the heater ducting for the Climate control (and air con low temp kill function).

I bow to your better knowledge of Octies. In fact, having two sensors might explain why replacing one didn't work (i.e. they replaced the wrong one...)

Ken is spot on. There are two sensors.

The one your after is "Ambient Temperature Switch -F38-". According to what I've read its clipped into place in the left of the plenum chamber. It controls the magnetic clutch on the aircon compressor. Disengages the clutch when the temperature drops below 0 degrees (2 degrees for pre-1999 cars), and re-engages once up to 5 degrees. (Anti-icing protection for the evaporator).

Doesn't fill you with confidence that the Skoda garage didn't replace both of them

Ken is spot on. There are two sensors.

The one your after is "Ambient Temperature Switch -F38-". According to what I've read its clipped into place in the left of the plenum chamber. It controls the magnetic clutch on the aircon compressor. Disengages the clutch when the temperature drops below 0 degrees (2 degrees for pre-1999 cars), and re-engages once up to 5 degrees. (Anti-icing protection for the evaporator).

Thanks to all for the responses, only one question on my mind now, where is the "plenum chamber"? please.

Plenum chamber is just in front of the windscreen.