AC stops blowing at high RPM
 

Hey guys,

New to the site, but I have an aging Ranger and Expedition, so I imagine I'll be on this site pretty often now.

My 2004 Expedition 5.4liter, has an issue where the ac will stop blowing out of the dash vents and seems to try and blow out of the defrost when I get heavy on the throttle. This especially happens when I am pulling my 5500lb camper trailer. Sometimes I can pull off the road, restart the truck and it will magically work again for a few hours. It is very intermittent.

First mechanic said it was just a vacuum hose had come loose, he put it back on for $20.


Second mechanic said we need some kind of blower box diverter assembly, but since we were in the midst of a 9 day trip, they just zip tied it open so it could only blow out the dash vents, no defrost or floor. $85 later and one hour down the road and the ac slowly stops blowing again.

Took it to the ford dealership, and they say it needs a new high side service valve and new vacuum lines, $750 total.

I do not want to spend $750 and it not actually fix the problem.

Any ideas if the Ford service tech is on the right page?

Thanks!