air con latency

[Dino]

Since the cold snap, when i start my WRX in the morning from cold, the air con takes about 4 mins before it starts to recognise its actually cold before putting warm air out. The aircon dial is set to 24 deg or set higher so it should know its only about 1-2 in the car cabin. Does anyone know where the internal cab air temp sensor is located? OR is there some other reason why the air con heater takes a while to register and kick in? Thanks

[Gambit]

I believe its in the unit with the temp dials. But not 100% sure.

[Scooby Pete]

Where's the heat going to come from? the system has to wait for the water to get to temp before warm air comes out. Mine always takes few mins to warm up. If I need to demist I just set the dials to windscreen, full temp, full power and then switch the AirCon on.

[Dino]

ok thought I'd ask because my wife has a Volvo (ugg) and that starts heating the cab immediately because there's a thermo-sensor in the dashboard that measures cabin temp. So I thought these things were sort of standard in more modern cars... but perhaps not?

 

I did look around this morning and found there's an interior cabin temp sensor pin hole next to the fan speed control dial.

 

Also, found out the air-con compressor actually doesn't come on below 0 degC to protect it. This is regulated by the exterior temp sensor behind the front grill. But once the engine has warmed up a bit it will start to work. So, even with the A/C screen blower on, it will only A/C blow when the engines warmed up a bit so that the exterior temp sensor is above 0 degC.

[Gambit]

I've learnt something today. I never knew they didn't come on below a certain temp. [emoji4] and at least ypu know now I guess. [emoji106]

[Dino]

yeah, I cleaned the temp sensors with some electrical switch cleaner today. That's made a difference too because the air temp detection is much more immediate now.

[Gambit]

Yeah I know when I was putting in the car pc my sensor or what I believed was it. Was full of fluff and dust.

[Steveuk260.Esq]

These days manufacturers are putting electric heating coing in the air ducts, these is especially true on diesel cars as they take a lot longer to warm up. Older cars are relying on coolant temperature hence in older cars cold coolant = cold air.