Air Conditioner Problem

I may purchase a 1997 Buick LeSabre Limited with 135,000 miles. I noticed today on a 140 mile trip that the vents on the passenger side blow hot air when the air conditioner is running. The driver’s side and rear vents blow cold air. What may be the matter and how do I go about getting it repaired?

That sounds like a blend door or air control door problem. On many cars these are controlled by vacuum, so you may want to look for a loose or missing hose.

Thanks for your reply. Since I posted the problem, I took the car out to get dinner and all the vents worked fine. Then, after dinner the original problem presented again. Anything meaningful with from this experience?