I am having a mysterious problem with my heater. The problem is that there is no heat. I am speculating that it could be the hot water valve that allows the hot water to flow into the heater core, but I do not know how to test this theory. I don't think that it could be the heater core b/c I would think that would be evidenced by a leak or something. The only other idea I have is that the vacuum actuator that opens the heater flap isn't working, but I would think that would be the least likely scenario. Does anyone have any ideas? Thanks, John Weaver ETDOC RED DMC #10527 [Non-text portions of this message have been removed]