AC / Heater problem

[bddadles 1]

Good Afternoon.

I think I may have a problem but not sure of the source. I have a 2009 Passion and the AC normally blows real cold. But lately I can be running down the road and the AC is blowing nice and cold and it will seem to start blowing warmer and warmer. I'll slide the control all the way up to hot and then back down and it will start blowing colder again. Where do I start looking for the problem?

Low Freon?

Bad sensor?

Please provide direction. I'm in South Carolina and it is warm.

Thanks.

Brad Dadles

Edited June 5, 2016 by bddadles

[MikeT 744]

It's likely a fault in the heater air blender door. That is thermostatically/electrically operated and its control system has probably gone spastic.

[bddadles 1]

Hi Mike,

Is this something that can be cleaned or adjusted or is it replacement? Plus how do I get to it.

Thanks.

Brad

[MikeT 744]

I don't know but Valeo which probably made this system for smart made a similar one of the Peugeot 405 I used to own and it would do the same thing.

[stevenwatsonb 0]

I had something similar happen to my '09 Passion Coupe and when I took it in for an overhaul after selling off my late wife's car the cause was the radiator fan (some of the brushes in the fan's motor had failed, so the fan would only spin intermittently), which apparently is also important to the A/C system. Once the fan was replaced it worked as usual. If you have an OBD device like Automatic with DashCommand for iOS or some similar setup the easy way to check is viewing your fluid temperatures while driving; here in Florida mine runs around 180-185 degrees; at 250 the engine overheat warning light will switch on.

 

You can also take it to have the refrigerant levels checked; it could just need a top-off. Getting to the proper fill port is a chore, though, as it's buried inside the front compartment with little if any clearance.

 

Replacing the radiator fan is expensive because it is BEHIND the radiator rather than in front of it, requiring the mechanic to basically tear down the entire front end of the car (I believe it was a 4 - 6 hour procedure when mine did it). The fan assembly itself was about $150. Unfortunately they didn't put my front end back together correctly so my outside temperature sensor no longer works right and the front left panel protrudes and catches on the door (need to fix that at some point).