No heat in 1999 Ford E-250.

99 Ford E-250
4.2l 6-Cylinder

The heat is not working at all. It's not the thermostat, and both hoses leading to/from the heater core are hot, which (to me) means that it's not the heater core either.

So to my knowledge, that leaves heater control valve failure, or the blend door being stuck. I am leaning to the latter, but do not know how to troubleshoot it, nor where it's even located precisely. Is it in the heater box? Near the firewall?

Any other ideas would be appreciated...

the heater core is located in the heater box wich is located under the passenger side dash, it has a black plastic cover over it with a few screws in it. you will have to undo the cover on the dash and there is a lot of metal brackets in the way but they only have a few screws in them. to get the heater box open you will need a universal joint for your ratchet it is kind of tight fit. once you remove that you will see the heater core attatched to a black box and if you look in the opening of the box you will see the blend door.

Good luck and if you need more help email me at: c_frank@alltel.net

Hi digital_precisions, I know your post is a few months old but this may help someone else if you have already figured your problem out! Anyways working on a 2000 ford I think they have the same heater controls there is a potentiometer hot/cold control on the dash that controls a servo that in turn moves the blend door that cfrank2 refers to the servo is mounted on the right side of the heater box it is a white 4"X5"x1" with a white shaft going into the heater box try yo see if the shaft is moving when you move the heater control from hot to cold and back it moves slow and quiet (~6secs.full movement) if you see it move then it is probably the blend door is broke at the point where the servo shaft goes in to it. Hope this helps :)