I have an 07 EX-L (I4 AT5), with a problem in the HVAC/dual zone climate control system. When in Auto mode, the system is blowing air that's way too cold, to the point that I have to crank the temperature way up to be comfortable.

I ran the HVAC diagnostics described here. There were no trouble codes showing, but the sensor test shows an obvious problem: the "In Car Temperature Sensor" was showing 28°C/82°F, when it should have read *at most* 20°C/68°F. This makes sense -- the sensor is giving a too-high reading, so the HVAC is working overtime to cool down the cabin.

Does anyone know where the In Car Temperature Sensor is located? Has anyone had a similar problem, or replaced one before? I haven't been able to find many posts on this exact problem, so not sure if I should try to repair sensor or just buy a new one.

FWIW, I noticed two other things with the sensor diagnostics. First, the "Evaporator Coolant Temperature" is measured in degrees Celsius and showed a value of "03" -- not sure if that's normal. Second, Ambient Temperature was a degree warmer than the digital gauge beside the trip odometer - a minor difference but I'd expect them to be identical.

Any advice greatly appreciated.
Nemo

 

The in-car temperature sensor is located behind the gauge bezel (directly under the temperature gauge area). There are slits in the bezel, which makes it looks like a vent.

 

redbull-1: I owe you one. I fixed the problem about 30 minutes after reading your response. The sensor had accumulated dust across the narrow-gauge wire that measures temperature. As soon as I cleaned that off, the temperature immediately dropped down to what it should. If this happens again, I'll just blast that little bevel / vent with some compressed air before taking anything apart. Thanks again.

 

Glad to hear it's fixed. I kind of suspected it may be partially blocked. Most people looking at it may think that is a blower air vent (outlet), when it is not.

 

Darn, cleaning the sensor only helped for about an hour. My local dealership has a new sensor for about $50, but I'm just wondering if there's anything more I can test before spending the money. For example, I'm wondering if the sensor is malfunctioning for something other than electrical reasons -- is it possible the clear plastic tube it connects to could be obstructed? Also, is there anyway to confirm what the accepted range is for the various sensor readings -- this would be useful to confirm if the problem is more widespread than the one sensor.

Thanks again.

 

Just spent $50 on a new sensor, made no difference.
My problem seems pretty rare. Any suggestions on what to do next? I'm wondering about other resources I'm not aware of, that specialize in HVAC systems...? I'd be happy to buy a manual if it would help.

 

Is air too cold for both sides or only one side?

If one side, suggest checking the air mix motor is cycling correctly when desired temperature is adjusted. Motor should smoothly change position from cold to hot position.

good luck

 

Good question. I drive alone 99% of the time so I never use the dual function, but I'll see if that's an issue. I'm also wondering if the solar sensor might be affecting the cabin temperature reading, but I can't confirm anywhere what the acceptable values for the self-diagnostic sensor readings are supposed to be. Anyway, thanks for the reply.