While I was driving tonight I noticed that my heat wasn't working. I had been driving around for almost an hour so I know the engine is not cold. I had the heat on at 83 degrees on both sides, but i felt cold air flying through the cab still (windows down). I proceed to roll windows up and put my hand next to the vents and its ice cold... wtf???

When I get home its still the same.. i turn the heat up all the way to Max heat. after about 10 seconds I can feel it start to warm up. i adjust it back down to variable temps and it feels like its working appropriately now.

Anyone have any idea of what could cause this? I had this happen the other morning too but the passenger side was cold and driver side was blowing heat like it was set to... thx in advance!

Check water level in radiator and overflow bottle.
If that's OK check thermostat

^im going through that right now...this morning it was cold and rainy so i put on my heater but the air blowing through the passenger vents were cold even though my side was pumpin hot air...im gonna make an appt to get it checked out on mon.

It's most likely the water valve under the hood near the firewall. This valve controls water flow to the heater core and sometimes it sticks. Many times it's found to be slightly leaking when it starts sticking.

Mine is the same way, I have to put it on the max heat and then back it off once it gets hot. If I put it on anything besides max heat it's dead cold. You can pull the control cable off and move the valve by hand to test.

There's a thread in this section somewhere with a step by step for replacement.

sweet thanks for the input guys, definately going to check everything you mentioned. much appreciated!

Might I ask why you'd be running the heater in August? Is it really that cold in your neck of the woods this time of year?

^awesome, thanks I hate cars. this past weekend was in the 60s and rainy...i got all drenched so that's why i put on the heat...im sure Vancouver can get pretty cold and rainy too even in the summer

Yes the NW doesn't know what season it is... EVER. although it has been warm, I was only using the heat real early in the morning, plus i like to have my windows down 24/7 so ya

I just experienced the same problem this morning! My windows were fogged up this morning so i turned on the the defrost and after my 45 minute commute half of my front windshield was still fogged up! The driver side was clear and the passenger side was still completely fogged up.

Any ideas out there??

Right there.

do you guys have a door actuator issue in the heater control?

I turned the heat up full last night while driving thru the mountains and no heat came from anywhere. Today while playing with the voice commands the heat came on fine and blew from the bottom vents. Is the system designed to only blow heat from below or is there something wrong?

Thanks

So far so good with the door actuators. The only somewhat common issue seems to be the water control valve (the on/off for the heater core) sticking. I'm actually not sure how much of it is the sticking valve vs how much is the weak cable actuator. If I pull the cable off the valve, the valve moves fairly easy and the cable moves as it should too. But when they're hooked up together the water is only turned on when I put the temp to it's highest setting. From there I can turn the temp down and it works fine.

Did you try changing the mode to vent and it still only came out of the bottom vents?

No. This morning I tried the heater and it seemed to work on both bottom and mid vents. It's like the heater didn't work at all earlier but is fine now.

Here it is..

F-167: Heater / Water / Coolant Control Valve DIY

https://acurazine.com/forums/showthread.php?p=11390744