I got the Air Conditioning working on my 71 but it dies when I place it in the Max AC position. All other positions work fine. Any ideas that could cause the AC Max position not to work?
If the compressor or the blower stops working then it's the electrical switch. If you just stop getting cool air out of the vents then it's the vacuum switch.
Check the vacum lines that feed into the firewall behind the distributor. They are prone to leaks. and than check them going to the actuators. I'm assuming that you are not getting air through the main vents but the system is working.
There is a high blower fuse, it is a 30amp inline fuse. It is located under the hood on top of the drivers-side fender well, near the horn relay. It is supposed only to supply power to the motor when the switch is on high.
It is very common for that fuse to blow.
Good luck!
If the Compressor and blower stop in Max then the switch in the control panel is out of adjustment... If just the blower stops in max or high speed.(which may be what's happening) there is an in line fuse in the red wire that runs along the driver's inner fender to the horn relay. If that is good the check the high speed blower relay on the evaporator housing.
Bluevetteman there nailed it , the fuse holder should be clean and intact too, that white thing next to the horn relay which doubles as the main power distribution point
also, that hi speed blower relay on the a/c is right next to the exhaust manifolds and mine got baked pretty well, you know....off the road, in the garage, hood down glowing cast iron heavy as hell cooks everything in site with NO air movement....well those wires and plug and the relay were moved to a spot on top of the evap housing....be super careful how you do this though place two very SHORT screws well located so as not hit the evaporator and destroy it....;-)))
A/C question
