Dragged home the new tent trailer today (I'll post pics later). On a couple of occasions today I had the HVAC fan going, occasionally switching on the A/C. It was about 30 degrees C on the highway (about 85F). The HVAC would suddenly switch to the defrost vent and would not switch to any other setting but "OFF". I made a fuel stop and popped the hood to let some heat escape while I fuelled. After that, it never happened again.

Any ideas?

Mine does the same thing all the time(when I'm back in SD),if you are going fast enough into the wind it seems like the vent controls are overpowered by the incoming air.Don't have any fix for it I just ignore it mostly(by switching to defrost so as not to damage anything,or max a/c if using the a/c).If you are still under warrenty take it in and have it checked.Really windy conditions really play h#$l with my HVAC,was it windy when yours did it?

Dead calm, just hot. Already have 143,000km on my '03.

This usually means you have a vacuum leak. I do not believe the engine/ac would overheat when going down the HW unless something was wrong. When the engine is under a load the vacuum will go down since the intake is open more.

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-Atlantic Blue
-Air Ride Rear Suspension ; OME/Rustys Lift ; Powertrax Locker ; Moog Lower Ball-Joints ; 245/70/16 Yokohama Geolander A/T-S's on MOABS ; Flowmaster 50 SUV
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