I'm cooking!!!! Turn off the freakin heat !!!!!

[72stepside]

When I drive the truck, no matter where the heater/defroster selector is, there is heat coming out of the heater box.

I have checked the inline valve and it is functioning property. When it is off, you can't blow air through it. The temp selector cable is working correctly, fully shutting the valve off in the 'low temp' selection.

The doors in the heater box appear to be moving correctly. When I have the selector to the off position, you can tell the fan isn't moving any air, but there is still air coming from this area

Next time y'all go for a ride, feel down there with the heat off and tell me if y'all feel any air. It might just be that I live in Florida and it is hot as fire down here right now.

If I can't find a solution, I'm gonna have to bypass the heater core so I can stand to drive the truck.

Any help is appreciated!!!

[Whoaaanelly]

If you don't have a heater control valve in the heater hose in the engine compartment, then the heater core is circulating hot water all the time. I have a heater control valve in mine (a 67), but I'm not familiar enough with these trucks to know if all do. It may not be working if you do. To test it, turn it to the off position and run the truck to temp. If both heater hoses are the same temperature at the firewall, then either the cable needs adjustment (it's not fully throttling the valve closed) or the valve just needs to be replaced. If it's vacuum actuated, then make sure it operates when you change the setting in the cab (although I don't think these trucks ever had these). If you don't have a heater control valve -- add one. You can either leave it closed during the summer and open it during your frigid Florida winters. Or you can run a remote choke-type cable to it to adjust it from within the cab.

[71 LONG BED]

I agree, the under hood valve is not adjusted properly or is not working.

[FORDification]

It's also possible you have the valve on the wrong hose, allowing hot water from the engine to come into the core but then get stopped on the way out.

For summertime use I think I'd just bypass the core altogether.

[CH3NO2]

sounds like you need to reseal the dampner door in your heater box. If it does not seal,when your moving all that hot FLA. air is coming in.Belive me it's no cooler here in Tampa.

[dotcentral]

Those valves can wear over time. My last truck the passage had worn about twice as large as stock. I had the same problems you were having until I replaced the valve, then the mystery heat was gone.

[steveheer]

Yep, me too! Last summer mine seeped just enough to give enough heat to be VERY annoying!! New valve and no more unwanted heat! Like was said earlier adjusting to make sure the throw turns the valve all the way off is also important--