Daddy Mark

I have had this problem since I bought the vehicle 2 yrs ago w/ 30k and forgot to mention it to the dealer when it was in for other repairs under warranty (hindsight....)
The controls to switch between vent-floor-defrost have always been very slow, sometimes 5-10 minutes to change airflow. Yesterday it wouldnt adjust to any vent and no air would blow from the vents. The temp was nowhere near the 90 degrees I had it set on (30 degrees outside). Does this sound like a blend door actuator or dash control unit? The truck has 50k now and is out of warranty so TSB 08-23-6 wont apply.

Good old Bill

Am a little confused here. Where does the air blow from? If its defrosters only, they default to defroster if there is a vacuum problem. Usually a broken line engine side of the firewall, forward of the glove box. If its a temperature problem, do both heater hoses seem to be the same temperature, grab them with your hand and feel?

Mod (Ret.)

Do you have the manual control (3 *****; one selects fan speed, one selects temp, and the 3rd selects the outlet for air to flow), or do you have the fancy module controlled unit?

In any event, carfulley remove the trim ring from the radio/AC/TEMP/VENT center selection. Then remove the radio. This will gain you access to some of the vacuum canisters that shut/open the various duct work to control the direction of airflow. Start the engine and select various vent outputs. Check the operation of any canisters, checking for vacuum leaks, loose or broken arms (actuators), etc.

If none of the vent options work, check under the hood for the main vacuum source line; however if this were broken or removed, I'd suspect a rough idle, or poor running engine.

If your AC/heat is the fancy module controlled unit rather than the simple dial type, I'd suspect that it is at fault. Pricy too.

Daddy Mark

The air does blow primarily from the defroster, even if it is very little air. Sorry for not mentioning where it is coming out. I do have the fancy module controlled unit, King Ranch Super Crew 4x4. And now that the vacuum issue is on the table I should mention I took it to a local dealer for the brake vacuum line TSB two days prior. I did notice a slight rough idle when accelerating hard right after that. I will check the vacuum lines forward of the glovebox for a disruption and heater hose temps. However, the sluggish operation of the controls wouldnt be vacuum so I will pull the facelplate and check cannister operation.
I will repost once I know more. Thanks, Bucko and Bill, for the quick responses... I hate spending money at the dealership.

Mod (Ret.)

Dallas huh? I live in Coppell.

If this started after you had work done under the hood, it's possible the tech removed a vacuum line either intentionally or by accident during his work. If you do take it back to the dealer for them to repair this vent selection problem, be sure to let them know this fact. If they find that they caused the vacuum problem, there should be no charge to you.

Hopefully they will be honest about it

Daddy Mark

Thanks Bucko, I really appreciate you sharing your knowledge with me. Actually I live in Rowlett, at Lake Ray Hubbard, grew up in Lake Highlands.

Interesting turn, I took the truck to the dealership and let them know what the issues were after the TSB was performed. They inform me there is some wiring near my adjustable brake pedal that has pulled loose/broken and is causing the problems with both the temp and vent adjustments. The service adv. informs me there is "absolutely no leaks in the vacuum system". The tech says the control module is functioning properly as is the blend door actuator... It will cost $190 to repair, including diagnostic charges I'm sure. Is there any wiring on the drivers side that would cause these problems? I'll gladly pay that instead a new actuator or control unit but dont want to be ripped off. Thanks in advance for your time!

BlackedOutFord

On my 06 i had the same issue but it accually turned out to be the blend door actuator and the wires got pulled loose the wires had actually started to pull out of the back of the connector i was able to fix those in about an hour if you are any good at it take a look and give that a try me doing that alone saved me about 130 bucks from the shop but each case is different just a thought.

Mod (Ret.)

I have the "simple" unit in my STX; 3 *****. Those electronic air select units are obviously more complicated than the simple unit.

Crawl down by the footwell and see if you can identify what that tech saw. If it's that obvious, and you're good with a soldering iron and heat shrink, fix it yourself. Dealers get in the area of $90.00 an hour for just labor, plus parts. Minimum charge is 1 hour. Don't know why they'd be performing a diagnostic charge though....

Daddy Mark

I went to the dealer yesterday and got the tech to show me what the issue was without offending his sense of honesty. There was some disassembly of the vents and such on the drivers side center console near area to find the short. The wires leading to the blend door actuator had pulled loose and he showed me where it was. Sounds like what "BlackedOutFord" experienced, how the wires got in the way of the brake pedal is hard to see though. I told them to go ahead since I haven't soldered in 20 yrs and their work is warrantied. Much better than the other possibilities of an actuator or control module replacement. I assume all will go well from here. Thanks, everybody, for pitching in with your expertise! I very much appreciate your help and hope I can return the favor or pass it forward.