Yes this is exactly why the Autotemp in my 70 has been screwed up for years. In my case BOTH the check valves are bad (using the service manual test, that is....) There are a few vendors who have NOS parts but, at $40 a pop, I'm not ready to buy. Mostly because there's no guarantee that the NOS part will work and they're not returnable. I've take one of my old ones apart and see that a plastic disc is force fit into a plastic cylinder. In my opinion the cranking that occurs is quite likely to happen from age in an NOS part. See the parts here: http://bos-engel.com/imperial/theworks.jpg I'll keep looking until I find a junkyard car with a good pair. Pete in PA Date: Fri, 12 Nov 2004 15:06:04 -0800 (PST) From: David Duricy <desotobravo@xxxxxxxxx> Subject: IML: AutoTemp II Insight <snip> Now the hiss was gone, but the fan would only come on in DEF or HI DEF. After DEF or HI DEF had been pressed, the fan would stay on if AUTO or HI AUTO were pressed, but neither AUTO nor HI AUTO would trip the fan if pressed first. This is a symptom not listed in the service manual. The cause turned out to be a faulty number one check valve in my replacement vacuum harness. With a good, used check valve installed, the fan came on just as it should in all modes, and the AutoTemp is working great. ----------------- 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