Jeff Ford
January 1, 2003

Step By Step

View Photo Gallery
Musing about what to do first are Dana “The Cheater” Chetham (white T-shirt and legs), Bob “The Big Kahuna” Myhrer (next to Dana), then left to right, Curtis Clark, Doug Greshian, and Mike Fleshman.
Our 429 CJ is complete and has all the components for the A/C to work—but it doesn’t. We suspect an electrical problem.
Al recommends a good set of gauges for the type of refrigerant you have. If you have 134A, you can get the couplers and use your R12 gauges.

Air conditioning can be a cool thing—pun intended. When your vintage Mustang is so equipped, especially in the deep south, where summertime temps can reach the mid- 90s and higher, it can make the difference between “let’s go out” and “never mind.” Of course, if you ask southerners about the summer, they’ll tell you it isn’t the heat; it’s the humidity. The Select-Aire air conditioner of yore did a great job of cooling the cab and removing the humidity—when it functioned properly.

This story is about diagnosing a system with all its components, all in seemingly good working order: belts in place, compressor in place, and all lines attached. Obviously, if the car has a “bald spot” where the compressor is supposed to be, much of what we say won’t apply—but some of it will.

The car we are using is a ’71 Mach 1 with a 429 CJ and C6 automatic. This car’s air was working when it was bought but recently quit—no compressor function. So we contacted Al Sedita at Classic Auto Air and asked him to go over the car with us and recommend some checks the owner can make on his or her own—possibly saving a buck or two in the process.