[77newell]

By using a dual thermocouple temperature monitor I was able to learn a couple things about the dash heat in my 93 coach.

On a 40 degree outside temperature day the heater produced about a 40 degree rise when the blower was on low and a bout a 50 rise when on high. That was strange since if the heater core was limiting the heat those temperature rises would be reversed. It turns out that my air-rest vents are pulling air in and not pushing air out unless the fan for those is turned on high and then the output is pretty anemic. I'll have to tear into the heater box to find out how that is possible but it explains some of my limited dash heat. When I taped over those outlets, the temperature rose by another 10 degrees.

The other thing I learned is that the solenoid at the coolant boost pump is needed or the heat is always somewhat on. I had removed mine to determine if it was limiting my dash heat, it wasn't though it did allow the "vent" setting air to warm 10 degrees even with the lever on the heater control to be all the way to the cold side.