I had the same problem with my 96 PT42, the front heat control has a temp. control knob like a car that allows you toajust the air from the ventsto range from cool tohot. This heat control knob has a cable attached that goes down to a valve in theheater hosefor the front heat exchangers, and whenthe dash knob is turned all to cool it closes a flapper in the valve on the heater hose. The problem is that that the valve, even when totally shut, stillallows some of the heated coolant (antifreeze) to flow past and that keeps the front heat exchangers warm so the driver and co-pilot get warm air coming from the front vents.

I clamped off a section of the heater hose that the valve is in with 2 vise grips and I cut the hose between thevise gripsand put in a manualy operated 3/4" brass ball valve.Iput ribbed brass fittings in each end of the ball valve that adapted to my heater hosesize and tightened with hose clamps. With the heater hose clamped off with 2 vise grips andcuting my hose between them, I only lost a small amount of antifreezeand that was absored into the rag I had put down under my hose.

Now if it's warm out, I shut the ball valve offwhich completly stops the flow of warm antifreeze to the front heat exchangerseliminating the problem of warm air coming from the front heat ducts, this also greatly improves the performance of the front air conditioning, when it gets cool out again I open the ball vale and the system works as it did before. On my coach there is a hinged access panel on the botom of the dash in front of the co-pilots seat that gives easy access to thefront heater hose, you would have to find a easy access place to locate the valve into the heater hose on your coach. Theball valve could be located in the supply or return heater hose to the front heat and it would work the same.

Wayne

96PT42