Hey guys, I know that this is an old thread, but I am now experiencing the same thing with my SDL. I had the Monovalve rebuild kit installed this summer by my Indy, so that should not be the issue. Is there any way to troubleshoot the CCU? I suspect that it is the problem. It seems to work fine to control the fan speed, etc. when it is in AC mode, but no matter what I do, I can't get a drop of heat out of this beast. I also had all of the vacuum pods replaced in the dash as well, so they should all be working well too. I'm up in Indiana now and it's getting cold quickly! HELP PLEASE!

Rob