Very weird problem with my 1999 Lincoln Navigator (that I love.) The air conditioning works for the most part, except if I am going “up a hill or accelerating over 40 MPH”. I know this sounds weird but it has been doing this for two years now. The dealer is no help. The AC works and actually blows cold air, yet if I accelerate it seems to turn off the cooling system and makes a sound like it is blowing air but nothing cold comes out of the vents. If I let up on the accelerator, the air then goes back to working normal - weird right? I really need a fix here - as the dealer looked at it and does not have a clue. Anyone, anyone - if you can help I will be forever indebted!!! Thanks so much!