Hello,
Thanks for taking the time to read this. I have an 08 F250 SD that has 2 issues with the heating and cooling. 1st this past winter I could not get any heat to the passenger side of the truck. I have dual temp controls but only heat to the driver side would work. 2nd. Now that summer is here, my AC decides to not come back on after driving a short distance and turning the truck off. This is not every time but some days more than others. When it works it works great, so I'm sure it is not a refrigerant issue. And when is does not work, I mean the whole thing is non-responsive to any adjustments and 0 vent or air will come out. Then sometimes it will start working after driving a bit. Most times it will work again after turning the truck off and letting it sit for a bit. Seems like something is overheating and shutting down until it cools off.

Any help would be greatly appreciated.
Regards,
Im Spuds

 

Sounds like possibly a 2 fold problem. First Check to see if the compressor is spinning/turning when you have it on and its not blowing cold. If its overcharged the hi limit switch will prevent clutch engagement. If the ambient (or under hood) temp is high you will notice the problem then verses low ambient temps due to refrigerant expansion. In other words when its hot the refrigerant has expended above the high limit. Then once it cools it drops below that limit. Best way to see this is with Hi/Lo gauges. Take it to a competent AC shop.
Your second problem sounds like the passenger blend door actuator is faulty.
When you say zero vent air does anything come out the defrosters? If so thats the default for a vacuum leak in the HVAC or ESOF auto hubs. So you could have a 3rd problem. Commonly the vac lines feeding one of the hubs has a leak causing an in-op vent system.

 

droldsmorland,
Thanks for the reply. When the AC is not working, nothing works, no cold or hot air, no vent, nothing from any side or location, like it has been turned off although there is still visual power to the controls. In regards to the heating issue. You may have misunderstood what I was saying. During the winter, the heating unit works but only cold air will come from the passenger side. I can control the volume of air on both sides and direct the air from the control panel to any location like defrost, panel or feet, but nothing but cold air will flow from the passenger side in all these locations, but I can control the temp of the air on the drivers side.

Regards,
Spuds

 

When "nothing works" have you looked to see if the compressor is spinning under the hood? Somethings intermittent for sure, likely in the HVAC controls. You need to try to reproduce the problem for a good tech to zero in on the problem area. Something or some connector may be or has in the past over heated causing an intermittent connection. The lack of heat on the pass side sounds like a blend door actuator problem. The other intermittent problem could be as simple as a switch or relay to a bad printed circuit board(PCB). I dont see the two being related but I dont have any experience with the dual zone option, nor do I have a schematic to view. Unfortunately there isnt a quick fix answer here. Sounds like its time to dive into the dash. If you don't have intermediate to expert electrical trouble shooting skills you will need to take it in and have someone spend some time trouble shooting. Find a shop that your comfortable with. Maybe give said shop a not-to-exceed dollar amount so you dont get sticker shock when the prob is found. Dash boards are complicated to many parts, and do take a bit of time to trouble shoot. At 100/hr around here that can add up to 10 hours easy. Start with the blend door. Then look at other sub-component controls in the system. An in-hand Ford schematic & diagram is critical. They or you should start looking for over-heated components and with a wire diagram start eliminating the working items.
Also look into any PSBs TSBs that may have been issued for this problem(s)at the dealer. They can look those up.

 

I've seen an issue similar to the heat problem you are having. Mind you it was on a kia SUV. It turned out there was an air pocket somewhere in the lines running into the heater core. I ended up running the vehicle up to temperature and yanking the coolant line off and allowing it to burp until it was running freely out. Might be worth checking out.

 

Your passenger heat issue or lack there of would be the passenger blend door most likely....do a self diagnostic of the electronic heating controls and it will tell you for sure. Passenger blend door is the one behind the glove box.