Suddenly no AC....

[kzxp398]

07 9-3 2.0t. Been driving it daily, suddenly today the AC won't work. Blower works, at 70 or lower it's just the fan, any higher it applies heat, and it's been well over 70. Possible cabin air sensor or is there another common issue?

Note - The previous owner bypassed part of the connector under the bumper in front of the driver's wheel, as that's the only common issue I've found thus far.

[Digger]

Low Freon pressure in the line set and the compressor won't kick in, jump the low side line switch, if the compressor kicks in you are low on Freon, if it doesn't, check all your fuses and if you still don't find the problem it's time to pay for testing.

[kzxp398]

Yuck. I hate having anyone else touch my vehicles. I did find that there is a missing ambient sensor on the bumper. Going to put the new one on tomorrow, weather depending. I hope it's either that or low freon. Easy fixes, otherwise......I dunno. Odd it just quit and suddenly blows heat when set to 72 or higher, when it's 75 or higher outside

[Digger]

Sounds normal to me, the controller moves flaps to close off cold and let in heat. If you have hot coolant in the heater core, when the air moves through the coil it gets warm. When the controller moves flaps to cool, if the compressor is running your coil gets cold and cools the air as it moves through.

Suddenly is the key word with climate control AC, the air control motors almost always make some noise when they start having trouble moving the flaps before they beak completely.

[kzxp398]

Checked it today, didn't hear anything abnormal, but that doesn't mean something there isn't wrong. Rained too much to do anything else. Maybe tomorrow. Scored a new(used, better condition) central vent, Valance, full size spare, and washer nozzle bits from a salvage yard, and have the new temp sensor to drop in/rewire. Also...I didn't realize the outer casing on the brake light assemblies was so cheaply assembled. Lost the casing a few days ago. Got a replacement, it's separating as well. Good thing I keep a variety of extra sealants handy.

[kzxp398]

External Temp sensor. All working properly now!!!