Amongst all the trinkets inside the car behind the steering wheel lies the cabin temperature sensor for the climate-control system. It is not very exciting, but it does serve a useful purpose. This video shows where I found it.

We’d been seeing some strange climate-control behaviour. The coldest setting sometimes gave us warm air, while 24°C was hot, hot, hot! Every so often the air con worked perfectly. I even saw an X in the corner of the display while it was behaving itself. That is the climate-control fault indicator, but it doesn’t point straight to the cabin temperature sensor. This was just one of the things worth checking.

We picked up an “Interior Air Temp Temperature Sensor” which appeared to be compatible with Holden VT, VX, VY, VZ, WH, WK and WL models. The VY’s automatic climate control uses cabin, outside-air and evaporator temperature sensors, plus a sun-load input. The outside-air sensor sits near the condenser; it isn’t measuring the condenser’s temperature. Refrigerant pressure and engine coolant temperature also affect A/C operation, but low refrigerant and high engine temperature aren’t separate sensors. Sun load helps adjust cooling and fan speed; LCD illumination follows the instrument lighting controls.

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