2003 Air Conditioning problem

2004 TC - Air conditioner fails during high speeds. Temperature coming from vents is 60 degrees at 75 MPH. At slow speed (city driving) temperture from vents is 47 degrees. Lincoln servuce caannot find the problem and says this maybe the norm. Any ideas?

... Any ideas?...

Consider the basics.

If there's any air (gas) bubbles in the refrigerant the higher speeds might be causing more turbulence than lower speeds, and decreasing refrigerant efficiency.
The increased air pressure coming into the vents under the windshield may be enough to slightly open one of the plenum chambers, mixing in warmer air at those speeds.
Q: If you drive 75 backwards, does the system warm up then too ?
Large buildup of bug parts on the radiator and condenser core cooling fins can cause erratic performance.

2004 TC - Air conditioner fails during high speeds. Temperature coming from vents is 60 degrees at 75 MPH. At slow speed (city driving) temperture from vents is 47 degrees. Lincoln servuce caannot find the problem and says this maybe the norm. Any ideas?
have had the same problem in the dealer that i work at.have had Ford engineers at the shop and they couldnt figureout the problem.somthing top do with the new scroll type compressors.