Robin and other interested parties, The Auto Temp system in my 70 drove me crazy for years. I had the normal "no blower until I first switched to defrost" and a persistent "farting noise" (as described by my 10 YO daughter) that seemed to come from the programmer/amp. After installing an NOS pushbutton assembly and considerable, back-breaking, vacuum line tracing/testing and electrical testing, I, too, discovered that BOTH of the check valves in my system were bad. These things are made of plastic and the two halves are forced together and melted into one piece. An interference fit inside causes one part to stretch and break (as visible in the pic). Because of this manufacturing method I have little or no confidence that NOS parts would fare any better than junkyard parts. Especially when NOS parts are going for $40 a pop with no guarantee that they will work (and are not returnable). My system remains unfixed. As a sidenote, these checkvalve were used in just about ALL Mopar big car A/C systems for years, regardless if they were Autotemp or not. Check your local junkyard. Here's a link to a check valve autopsy photo: http://bos-engel.com/imperial/theworks.jpg I've been meaning to shop industrial catalogs and piece together a replacement but have not done so yet. ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm