Weird Aircon problem

[Pinelli]

Hi all,
Got an aircon system behaving strangely, in that the front passenger gets beautifully cold air, while the poor old driver gets a warm breeze. So nothing wrong with the fan, but I don't get any of the cold air. Also nothing wrong with the aircon, as the passenger side is cold.

Wondering if there are perhaps two sensors in the front, one for each side, and the driver sensor is ready for retirement, or perhaps if there might be a mechanical problem under the dash where the cold & external airs are mixed.

Any thoughts?

Don't think it matters, but this D2 has the rear aircon which also seems to be working fine.

[sierrafery]

Hi, run a manual diagnostic routine on it(attached) maybe it reveals something, it doesnt have sensors for each side, only the sunlight sensor's inputs are used for side temp. management by the system, do that diagnostic outside better when it's sunny cos in the dark you'll get false sunlight sensor fault codes

i know even if it doesnt sound logical but in most cases a regas was the cure for that strange behaviour, especially if no faults are detected

[CU55TM Disco]

off topic, but is there a way to "reset" the auto values to my own prefered setup?

[biggin]

Hi all,

Got an aircon system behaving strangely, in that the front passenger gets beautifully cold air, while the poor old driver gets a warm breeze. So nothing wrong with the fan, but I don't get any of the cold air. Also nothing wrong with the aircon, as the passenger side is cold.



Wondering if there are perhaps two sensors in the front, one for each side, and the driver sensor is ready for retirement, or perhaps if there might be a mechanical problem under the dash where the cold & external airs are mixed.



Any thoughts?



Don't think it matters, but this D2 has the rear aircon which also seems to be working fine.

Classic symptoms of a system that needs the gas topping up. Happened to me recently.

[Pinelli]

Thanks,
Are you able to explain how low gas can result in one-sided air con? Are there two evaporators perhaps, with the passenger side using up all the 'cold' first?

I guess its easy enough to get the gas pressure tested. Will let you know what I find out.

Edit: Did the manual diagnostic test, and came up with no faults. Will get the gas tested!

[sierrafery]

In a nutshell: there is a thermostatic expansion valve on the evaporator which can keep the cold one side if there's not enough pressure. Real life experience has prooved that low pressure can have such symptoms even if it doesnt sound logical at first sight ;)

[northiam]

http://www.aulro.com/afvb/1831097-post3.html


Try the above first

If switching the rear ac off improves the front this would indicate a lack of refrigerant.

Also compare the blend motors and flaps to the better side incase you have a jammed flap or faulty blend servo.

Regards

[clubagreenie]

Check the blend motors first. They adjust the mixture of hot and cold air, as the heater is constant flow it's always hot and if the flap os stuck at the right point it won't necessarily be hot but warm enough to overcome the A/C.

The D2 internal ambient temp sensor is on the right side of the steering column, theres a small square grille with a fan behind it (it's also the source of an annoying rattle that can be overcome by greasing it's bush). The single sunlight sensor is the round knob in the centre of the dash by memory.

I think theres a second dryer in the rear circuit, I think I remember seeing one back in the corner. It should have a sight glass and you shouldn't see any bubbling there or in the front one.

[Pinelli]

Regas done, and seems to be working much better. Cheers all.