byrd48

Hi,
I thought i would post this out of amusement and with the hope it might benefit others troubleshooting a lack of heat. In my case, the heat was lukewarm at best, barely warmer than straight cold air. I popped off the plenum cover while the engine was on with the heater running and could feel a blast of warm air coming from the heater core, but when I put the cover back on, only cold air came out the registers.
The mechanism that moves the blend door (photos posted by others) will allow the temperature **** to be turned whether or not it actually moves the blend door. I stuck my hand in and felt around as best I could and it felt like the blend door was only moving half way. I stuck the digital camera in through the hole (and was lucky not to drop it by the way) and started taking photos.
In the first image (img_2015), the door is open in the cold air position.
Img_2020 shows it in the 'closed' position, but only halfway closed.
Img_2025 shows the culprit.
Now the mystery is how it got there. I wonder if the defrost vents drop straight down to the blend door area.
Best wishes,
Jon

byrd48

In case it's not obvious, that's a pencil

cgossett

haha great thanks byrd. I was expecting an animal

kevinwil

It drops straight down to the blend door. I posted in another thread about this solution!

Glad you found it!

KyleP

Link to said thread??

I know, I know...use the search function but I'm lazy

kevinwil

No worries, I'll elaborate here. The defrost vents for the windshield don't have screens, you can drop change and other things between the firewall and the dash board. The opening is also directly above the blend door. When an object is stuck in the blend door, the symptoms are exactly like those of a stuck thermostat. When you go fast, the radiator cools the coolant and cold air blows out when u put the heat on. Only when you are stationary will the heat get hot.

The mechanics behind this pen in the blend door problem are different though. The blend door blends air from the heater core and from a trap that leads to the outside. When a pen is stuck in the door, that trap is open and as you speed up, the ratio of outside air to heater core air increases cooling the cabin airflow, leading one to think that the heat is coming out cold. You can reach the door and were if there is something blocking the door if you remove the glovebox and the heater core cover behind it and reaching to the top left behind the blend door activating arm (white plastic).

Hope this helps!

byrd48

Well, I suppose if they didn't want to put screens in the defrost vents, they coulda put a trap door or something at the bottom of the air box to clean out anything that drops in. It was not easy to get to!

blake353

I have a question about heating problems. My heat works fine when I'm jus cruising. But when I get on it OR get above 55 on the interstate it starts blowing from my defrost. Exact same problem with my ac. Anybody know what's causing this problem?

kevinwil

Do you mean that the air just goes cold at highway speeds or that it stops blowing out of your forward vents and flows out of the windshield vents?

blake353

It does lose some o the heat but yes it goes thru my defrost only