The 68 system is quite different from the 74 system. This should be a very easy problem to diagnose and repair. I see no need for radical surgery at this point. The 74 system is a rather simple system when broken down into its components. ----- Original Message ----- From: ViaJoaquin@xxxxxxx Date: Tuesday, December 24, 2002 4:42 pm Subject: Re: IML: Auto Temp II > In a message dated 12/24/2002 3:04:50 PM Eastern Standard Time, > markblitman@xxxxxxxxxxxxx writes: > > > i depress the LO or HI-Defrost button on my '74 Imp to get the > fan working for a few seconds and then I depress the LO-HI- Auto > button and I hear the blend door close(or is it > > opening?) and then the A/C works normally.... > > Mark, > That is a solution that dates back to the original ATC, in fact it > is written in the 68 FSM! What happens is that the vacuum check > valves start to stop checking and that is the only way to fool the > system into doing what you want it to do. Since it is such a long > discovered problem, the only solution would be to live with it or > replace the switch and all the vacuum circuits. > > Roy > 67 Crown FDHT > >