Diagnosing a HVAC vacuum issue on a Ford F53
The AC/heat is switching to the defroster under higher RPM conditions on my 2006 F53 chassis Damon. It actually seems to be doing it now under low throttle steady state conditions as well. Obviously...
Forum Discussion
wolfe10 wrote:
Doug's answer IS spot on for any driver of a gasoline powered vehicle who expects adequate vacuum to operate the dash HVAC system under heavy load= low engine vacuum. Suspect a number are fit after a first drive in real mountains where sustained high throttle/low vacuum conditions are encountered.
No question, it will not magically fix other leaks in the system if they are large enough to overcome the supplemental pump.
BTW, that is the standard vacuum pump on a large number of diesel vehicles, since diesel engines have no vacuum. VERY common pump.
And yet those smarty-pants engineers with the coke bottle-bottom glasses and pocket protectors found it entirely adequate to just add a big vacuum accumulator to the system and all is good.....
Unless you have a mechanic who’d rather throw parts at the vehicle instead of actually fixing the problem.......
As a wing-wiper I served with used to say, “maintain it, or you’re in for a looooong walk home.’”
