So it's 45 degrees where i'm at and I just got back from driving my TL around for about 20-25 minutes.

I started the car and let the rpms drop to about 950 and than drove off for about 3 minutes.

I pressed the FAN ^ button to turn the fan up. The temperature on the display read 83 degrees but was still blowing cold air. I thought it was normal so I continued to drive.

3-4 minutes later I realized its still blowing cold air. I looked and noticed the air recirculation button was lit up orange. I pressed it to turn it off, to get air from the outside thinking the air from my engine should be warm so I should atleast get warm air.

With the air recirculation button turned off it still blew COLD air even though the display read 83F. I decided to turn it up all the way to where it says MAX and left it there with the fan blowing full blast. This is about 10 minutes into the trip and my car is still blowing cold as fuck air.

I thought to myself "maybe because the A/C is enabled" so i hit the A/C button and the display read 'A/C OFF'. Drove around for another 3 minutes and still COLD AIR.

Decided to put it on the feet warmer mode (The mode that displays air is being blown to your legs, but it also has the defrost icon) I had it on that, with the temp display 85F and fan speed on 3 or 4. By this time it's been 15-20 minutes into the car ride and the air is still blowing just as cold as I first turned the heater on as 10 minutes before...

This is the first time I turned on the heater mode in about 6-7 months. (Last time I used it was Feb/March)

From what I remember, the heater was working just fine in the cold months that I first had the car (jan, feb, march) and now all of a sudden it doesn't work.

Anyone know?

 

Basics 1st, check your coolant level. If the level is good, no leaks then you either have a faulty air mix motor which controls the hvac system regulating the temp of which air comes out of the vents or on the fire wall there is a coolant regulator that may be leaking or something is broken off. When you sit in your car, running just go from hot to cold listen for the blend door behind the dash board moving. That would confirm your mix motor is good, do the same test but have someone look at the firewall where the coolant regulator is and see if thats also moving. Best of luck.

 

https://acurazine.com/forums/3g-tl-2004-2008-93/f-167-heater-water-coolant-control-valve-diy-747304/

 

thanks you two. i didn't know where to start to diagnose it, but i'll start with the two advice you two gave me.

i'll report back with updates

 

tried the HCV. failed.

but while attempting to exchange it, i noticed my current HCV isn't clogged. i don't think it needs to be replaced. i moved the switch and it went from having no coolant come through to coolant flowing freely. so my HCV isn't clogged.

 

OK so the problem is that the cable that attaches to ny HCV valve won't pull on the trigger to open the valve up.

When I turn the valve by hand, the heater in the car works fine. When I close the valve and turn the heater on in my car and check, the valve is still in the closed position.

Does anyone know what I can do to check why the HCV cable isn't opening the valve as intended? I checked EVERY fuse by the drivers foot panel on the interior. All are fine

 

this is not a picture of my HCV. it's one that i'm using for reference.



this is the cable i'm speaking of. in the picture it's the blue cable located at the top right. on my car (08 base) it's black though.

that wire controls the HCV and opens or closes it. for some reason when i turn on my heater in the car, the HCV valve is supposed to open up but the cable doesn't seem to move to open the HCV

my HCV valve is not clogged. i can open the valve by hand easily and heater works fine.

 

UPDATE ---

My heater is working now. The cable that connects to the HCV properly opens and closes the HCV.

HOWEVER..... When I turn on the heat in the car, ONLY MY PASSENGER SIDE VENTS BLOW OUT HOT AIR. The 2 vents on the drivers side continues to blow out cool air.

I put the heat to 85, turned A/C off, and set the fan speed to about 4.

Placed my hand over the 2 driver vents and the air was still cool / mildly cold.

Placed my hand over the 2 passenger vents and the air felt hot and warm, just like how 85 should feel.

What could cause the 2 drivers side vents to still blow cool air while in heat mode, while the passenger 2 blows hot air just fine?

 

My girlfriend has what appears to be a similar issue in her '05 TL. She's able to get warm/hot air out of all the front ducts, but only cold out of the rear seat ducts.

She's freezing her kids out, and since I've been on this site because I just bought an '09 SH-AWD, she asked me to check for an answer.

 

Poor kids! I wish someone one here could solve this for us.

Here's a simple fix for your girlfriend. For the vents of the rear seats, you can slide the nob up or down. This closes and opens the rear vents. I belive you can slide it all the way down to close it. This should somewhat prevent the kids in the backseat from freezing!

 

How did you made it work!??

 

Dude...why not keep it in your own thread?

Post a pic of yours and we will know what your working with...in your thread.

 

The heater control valve was stuck closed. It wouldn't open up allowing the hot coolant to flow to the heater core. All I did was just physically mess with the valve and try to pull it open. I than cycled my temperature on my hvac system from full cold to full hot several times to make sure the heater control valve opens and closes correctly.

The heater control valve is located under the hood by the firewall (bulkhead wall). When standing in front of the car, its behind the engine near the top left side of the engine cover. You will see a black heater hose and a heater control valve with a small steel cable going to it. That cable is what opens and closes the heater control valve.