Went to use my heater, but no hot air. Blower works, A/C works. All summer when using A/C, I would have to adjust the temp **** back and forth to get cold air. Apparently something is sticking, WHAT? "99F350 SD 7.3Dsl A/T.
Coolant level OK. No leaks.

 

Heat! Were still months away from needing heat.

 

You need to hunt for a collapsed or broken vac hose.Remove the glove box and you will see some there.Does the a/c default to the defrost vents?

 

Last week I went from the dessert thru the mountians and it was pretty cool up there. 100 degrees plus down into the low 30's. Still had my shorts on then, but since I didn't have heat, I got out the warms closes'
I'll look for the vac hoses. thanks to all, to al good night.

 

I am working in Wyoming and it has gotten down to the lower 40's already. I just had the same thing happen and found the the electronic blend door actuator was not working. Vacuum has nothing to do with it, it is electric and it cost me $77.00 and it's a Ford item. Don't let the clowns on here tell you it is held in place with screws, it is not. Go get a new one and you will see what I am talking about.

I wish if people don't know what they are talking about not to post an answer, I have about had it with this board and people answers that are way out there when they have no idea what they are talking about.

I guess you have to be part of the "click" to get a real answer. Now if I ask a question about how big of a stupid stack to put in the bed I would have 100 or more people answer or how big of tire I could mount on a stupid truck that has a 15 in lift that has never been off the paved road.

 

Someones a bit touchy, but Barry is right. If the air defaults to the defroster then it IS a vacuum issue and YOU WONT HAVE HEAT. But if it deflects to the other vents when selected and still no head then you may be right. So really, whats the point in belittling others?

As for your heat issue, if its stuck on defrost, check for a vacuum leak. Mine was stuck on defrost and found the large O-ring in the 4wd hub was leaking. You probably would've never thought of it but its all one system and if the hub leaks a vacuum, the deflector in the cab won't work. If its not stuck on defrost follow grumpys advice.

 

I think someone needs some prozac lol. This place has yet to steer me wrong. And when I needed help people from here are the first ones to jump and help over my own family. Dont like this place...Then leave. Noone is forcing you to post up anything.

On the heater thing, Mikey is correct. Inspect your lines first. And if that doesnt work then work your way to the actuator.

 

There is no need what so ever for this type of outburst. Understandably not ever answer that you get here is going to be 100% right on the money but in the same aspect non of us are professionals. There is a possibility that whom ever answered your original question had a different model year and it did have screws or was relating it to another experience.

I have seen more good that harm come from this forum and have seen a lot of money saved. The people behind the keys here are honestly trying their best to help in more ways that just offering advice to those that need. You mention being part of the "click"? All I have seen is people being treated as they treat others.

 

Good Morning! Nicely Worded Jim. Not Everyone Has People Skills!

 

My hub seals have been gone for many years and the Heat and AC work fine.

 

My AC also only comes out the defroster vents. the truck is a 2000 and has manual hubs only( no vacuum lines down there). All teh lines under teh dash look great. Should I try and put a vacuum tester on all of the acuators? Could it have anything to do with the actual switch oin the dash?

 

My hub seals have aslo been out for along time. my heat and AC work just fine.

 

Are they factory hub locks? If they're aftermarket, someone could have forgotten to plug the lines. When you turn the key on, but don't start the engine, do you hear the vacuum pump running? Its on the passenger side fender. If you had a vac leak for a long enough time, the pump could have burned up running constantly.

 

Ill go check right now!!! The hubs are aftermarket WARN design but I dont se lines or even any place for tehm to hook up? Did all superdutys have vacuum locking hubs or is my setup common?

 

Well, believe it or not, there is more than just one reason someones heat doesn't work. I'm glad the ford place figured it out for you and I hope that did the trick. I hope you do decide to stay, we could really use someone that is always right and knows everything.

If your hubs have been replaced, then chances are you used to have auto hubs. You can look under the hood and find the vacuum pump on the pass. side fire wall and look for the solenoid mounted beside it. It will have the lines that run down towards the axle. All of our diesels have the vacuum set up as a diesel engine don't produce a vacuum like the gassers do.