Ok, I wake up this morning 50 degress here in Indy and although I turn the temp up to like 72 in the car no heat blows. Anyone run into this? I'm not even sure where to start diagnosing. My only thought is where the sensor might be that tells the HVAC what the in car temp is but I feel its probably made into the control panel.

2005 with Nav

 

The sensor that detects in cabin temp is located behind the knee panel on the drivers side. you'll see little slots where your right knee is when you sit in the seat. The sensor is behind there.

Your heater control valve is probably stuck closed. Try turning the temp to max heat and back to max cold a few times

 

Try to put the heater on high and leave it there for a while. It may start to work. I had this problem when I first bought my car and it's fine now. I thought it was not going to work then all of a sudden after a day out started working and it's been fine.

 

Thanks guys I will try the valve first. Anyone know how much the sensor might cost off hand? I would think if its the valve though that AC and fan should "back off when on auto because it should not be calling for cooling at all? Does this sound correct?

 

The sensor is what tells the fan speed to slow down.

The heater control valve opens to allow the coolant heat up your heater core and the air is pushed over the heater core which gives you warm or hot air.

I highly doubt the sensor will fix your problem

 

If your heater core is stuck closed its not allowing coolant to heat up your heater core therefore no heat.

You can visually inspect the heater control valve

 

^^^+1 on what he said and another thing he didn't mention is that some time with visual check the control valve looks good from the outside but the actual inside valve is bad since they made by plastic and could be deteriorate over time, looks for guiltar player DIY he had instruction of replacing one of those.

 

Maybe try the self diagnostic test? Once I wasn't getting heat to the passenger side for some odd reason, I performed the test then it started to work. Hopefully it works for you.

https://acurazine.com/forums/problem...m-ever-831545/

See post #3 and down....

 

I've got this weird problem right now too. Without having the dual controls on, I'll try to have hot air come through, but end up with hot air coming from the drivers side, but cold air from the passenger side.
Thanks for the tip. I'll try alternating between full heat and full A/C.

 

Feel the heater hoses before and after the control valve to see if any temp difference.

 

Look at my post above and perform the diagnostic test

 

Same problem on my 04TL the radiator stopped taking coolant from the reservoir, make sure you physically check the level of fluid at the radiator.