My heater is cold

[sandmann999]

Hello,

Now that it's winter, and averaging around 15 - 30 degrees here, I'm really noticing that the heater in my Bronco is not very warm at all. I'm not sure of anything that might be causing it, except the only symptom I know is that no matter what I do with the selection lever, the air always blows out of the defroster (on top). Anyone have any ideas why my heater air is only luke warm? I'm not even sure where to start. Thanks.

PS: I have an 81 300 I6.

 

[Seabronc]

That is the symptom of no vacuum to the control. The default selection is the defroster. Check the vacuum lines on the passenger side under the hood. You should hve a black line that goet thru the fire wall. It connects to a check valve that has 3 connections. One goes to the main vacuum tree, one goes to the vacuum reservoir and one goes inside to the control. Also check the condition of the vacuum reservoir. You probably have a break in one of these connecting lines, bad check valve, or bad reservoir.

A couple of diagrams attached including a picture if the check valve.

Good luck,

>-

 

[rebelskate]

as far as blowing luke warm, do you have a thermastat in it or has someone removed it?

 

[BLADE262US]

You can also swap the hoses around for the heater core sometimes it will get plugged up and if you swap them around it will unplug for awhile till the stuff goes back through the cooling system to the other side of the heater core tubes . Temporary fix till you can get your system flushed . /emoticons/[email protected] 2x" width="20" height="20" />

 

[sandmann999]

Thanks for all the info. The heater core was just bad. I swapped it out (it was only $25 for a new one) and now I have to turn down the heater so I don't roast myself. I love it, it's cold up here.

As for the selector, the cable simply came off of its runner (right behind the glove box). I put it back on and held it in place with a zip tie and now the selector works great.

 

[dmp0449]

That is the symptom of no vacuum to the control. The default selection is the defroster. Check the vacuum lines on the passenger side under the hood. You should hve a black line that goet thru the fire wall. It connects to a check valve that has 3 connections. One goes to the main vacuum tree, one goes to the vacuum reservoir and one goes inside to the control. Also check the condition of the vacuum reservoir. You probably have a break in one of these connecting lines, bad check valve, or bad reservoir.

A couple of diagrams attached including a picture if the check valve.

Good luck,

>-

Any body know how to get to the door that opens and close to shut air off to the vents and open for the defrost. i took the heater coil door off under the glovebox compartment and i could see the door shut crooked and not alowing it to shut the vents off so air could go the defrost vents.

 

[Yardape]

Thats how you get to it, other than removing the whole heater box assembly from under the dash

 

[gnarly_bronco_kid]

huh......doesn't sound like much of a heater to me... Yeah I had the same problems except for mine was the heater core and when that went out I was smart enough to drive it untill there was a puddle of radiator fluid on my floor.