Hello Ford Folks,
I've just joined this forum because I've inherited a 1996 F 250 Powerstroke with a 7.3 turbo diesel With just under 80,000 miles on the odometer. I had an older Ford Diesel in my business before I retired 10 years ago which I gave to the young lad who bought my business. I hope that I am not out of line by asking a question about my truck in my introductory message, but here goes. On a recent trip my AC froze up and melted the serpentine belt off. I had a new AC system installed. I discovered this AM as I was trying to trouble shoot a reluctant heater that the new AC actually turns on when the heater selector is in the mixed or defrost position & the heater doesn't work on any position. Any guidance would be appreciated.

 

Moved to 1994.5 to 1997 7.3L PSD forum and new thread started.

Welcome to FTE. You should be able to get some help here.

 

Welcome to the OBS 7.3 forums! Questions are what we are here for. The AC pump should run with the defrost to help take moisture from the cabin. The heat problem could be several things, from bad thermostat, plugged up heater core, but I'd check for a blocked up bled door in the heater box. Objects can fall down the defrost vents and keep the blend door from shutting allowing mostly cold air to blow in. To access the blend door, remove the glove box, then remove the 8-10 screws that hold the cover on the front of the heater box. You should then have easy access to the blend door.

 

Thanks Farmert. I will check that out & let you know what I find. I have already checked the heater core & found that water from a hose passes through with no problem & both heater hoses are hot to the touch.

 

Farmert, I took the cover off and the only thing that fell out was an old rusted screw. There was evidence that someone has taken the cover off before also. I could see no reason why the heater shouldn't work unless the rusted screw had some how messed up the works. I will know tomorrow as I will be driving it for a distance and will try to run the heater again.
Thanks for the help

 

The blend door operates off of vacuum. You might want to check the lines to see if any are broken as they are a hard plastic. There is one in the engine compartment by the passengers side hood hinge that comes to mind. I had a mouse take residentcy in my 90, and it chewed one of the lines under the dash. After a patch with with vacuum hose all things returned to normal.

 

Welcome to the obs brethren and to FTE
If the heater aint working, touch the heater core to make sure it doesn't have cold spots,once the engine warms up

 

I drove the truck yesterday morning & after about 35 miles or so the heater did start operating. I think that the thermostat is very slow in opening, at least my heat gauge seems to indicate that to be the case. I will replace it tomorrow & see where I am with the heater. Thanks for the help to everyone who replied.