2006 F350 air conditioner problem

[David Archambault]

I am hoping that someone can help me with my air conditioner problem.
When I tow my 2010 3400RL (in Arizona) I find that the air conditioner cuts off and blows hot air when I am pulling up the hills. All of my temp gauges read in the middle of their ranges. I do not want the AC to cut out on its own. I would rather cycle it off if the temp gauges rise.

Any Ideas out their?

[racerjoe]

There is a vacuum check valve that is failing. when you give the truck more power,vacuum drops out and without the check valve it closes the blend doors, when it does it, put your hand up on the defroster vent,the air should be blowing out of that. The defrost is the only vents that continue to work when there is a blend door failure.

[SlickWillie]

quote:Originally posted by racerjoe

There is a vacuum check valve that is failing. when you give the truck more power,vacuum drops out and without the check valve it closes the blend doors, when it does it, put your hand up on the defroster vent,the air should be blowing out of that. The defrost is the only vents that continue to work when there is a blend door failure.

So, is Ford still using vacuum for the HVAC ducts? The last couple GM trucks I've owned had electronic modules that actuated the dampers. I would think perhaps the truck was near overheating, and the computer is shutting the AC down to eliminate condenser heat.

[Carl n Susan]

I discovered my old 2004 Ford did the same thing. Pulling a hill on hot days (Mt. Ashland in OR (a seven mile 6% grade) when it was 100+ degrees and maintaining 55+ MPH) would result in hot air from the A/C. The local service people verified with Ford galactic HQ that it was the on-board computer shutting things down because the engine was getting too warm.

The water temp (and transmission temp) gauges are nothing more than glorified idiot lights. They read normal until it is too late. The best bet is a non-intrusive add-on gauge that plugs into the OBD port and displays the real numbers the on-board computer sees (and reacts too). After that it is best to back off when pulling uphill with a full load.

That 6.0L has enough potential troubles without adding overheating to the equation.

[Fire5er]

Carl,
Which "non-intrusive add-on gauge that plugs into the OBD port and displays the real numbers the on-board computer sees (and reacts too)" are you using? I have been looking at getting guages but don't want to do all the drilling on key engine parts that it requires. I would much rather just use a plug and play unit like you are talking about.

[CamillaMichael]

We just finished towing our Montana up I75 through GA into TN...picked up I81 North into PA and on into New England. The weather was hot and the mountains were steep...we are happy to note we did not experience any loss of a/c and the "idiot" lights never gave us any cause for concern. Just luck?

[Carl n Susan]

quote:Originally posted by Fire5er

Carl,
Which "non-intrusive add-on gauge..."

Richfaa is a big fan of the Aeroforce guage while others like the Insight product. I do recall, but I am not positive, that the 6.0L Ford does not offer a pre-turbo EGT value via the OBD port. If you want the info, you have to tap the exhaust pipe and install an optional probe. But the vendor is a much more reliable source of that information.

[thor]

the gauages that you might be interestes in are on line ones like bullydog orbanks oe edge products some come with pryometers gauages that check temps coming off the exhaust at the turbo plus trany temps and water temps .there is a good magazine out called diesel power that is for 3/4 and 1 ton trucks that have alot of info on such products.hope that helps

[coyoterick]

quote:Originally posted by Fire5er

Which "non-intrusive add-on gauge that plugs into the OBD port and displays the real numbers the on-board computer sees (and reacts too)" are you using?

I use the Scangauge II with my F350: http://scangauge.net/

It's plug and play and relatively inexpensive, I got mine for $135 on eBay. You can setup 25 custom "gauges" with it too - I've setup Horsepower, Engine Oil Temp, Boost Pressure, Injection Control Pressure, and Manifold Air Temperature on mine.

[David Archambault]

Thanks to everyone ... I appreciate the replies and pointers ....