Hello everyone,

the weather is changing here on the bay area and I just note that I don't have hot air on my truck,any one here that can steer to the right direction on solve this problem.
it blow air and everything but not hot air.

sorry I forgot to add that my truck have 390 engine and it is 1977 f250

Thank you,

 

I just went through this with my 78. Do both of the heater hoses get hot to the touch after the truck is warmed up? My heater control valve was stuck.

 

Also try disconnecting the heater hoses and back flush the heater core.

 

Hi Ljblue,

you have good suggestion I didn't touch the hoses, I will check them up, thank you for your input.

 

If they are not hot it could be the same valve or a clogged heater core. If they are different temps it could be the core too. Good luck and get some heat soon! It’s getting chilly around here.

 

do you have AC? AC equipped trucks have a vacuum controlled water valve inline with one of the heater hoses under the hood. Non-AC trucks control the heat via a cable connected to a door under the dash.
Also could be caused by your thermostat being stuck open and the engine never reaches normal operating temps.

 

Make sure the control cable that flips between hot and cold is attached. There is a small lever just under the glove box on the heater box. The cable should be held on by a star washer. Sometimes those fall apart and the cable can come off the lever. I only know this because mine did one time.

 

Hi jrotten67,

I will check the cable that you mention, thank you for your input.

 

Hello everyone,

I have on update in what I have found, the hose get hot, so what I did I move by hand what you see on the picture where I point.


Once i move this by hand then I start getting hot air on the cab

When I touched the hose were 🔥.

 

Hello everyone,

anyone here know why when I select on the can, for hot air the level on the engine compartment don't move? the one I show on the picture.

Thank you,

 

Des the lever slide really really easy? If so the cable might have broken or come loose from the lever. Would need to try and look up under the dash at the back of the heat,/cold controls or pull them to see. I missed where you said you had air. I dont have that so I may be talking out my butt....lol

 

what he said ^^^^
this is what the controls look like behind the dash...when you manually move the lever under the hood, it should also move in the highlighted area...

 

Hi jrotten67,

No the level is not that loose, it has some resister like it should.

 

Hi dlburch,

I will ask my son to move the level under the hood and I will check under the dash to confirm if moves, this cable on the drawing is the some that I move by hand under the hood then right?

thank you for your help.