Dashboard Heat not working (AC works great)

If you want to grab a copy of the Heater and AC manuals from Denso HERE

Sounds like your electric motor driven control valve on the outside of the dash is not opening up. You can can use a 9V battery to open and close by reversing the polarity.

Up until as late as 2002, Fleetwood was using Demco for their HVAC. If you have a Demco unit, it uses a blend air door and NOT a water control valve to control the temperature. If you have an Evens Tempcon HVAC, you have a water control valve, it will be attached to the heater hoses, right by the HVAC case (under hood on passenger's side). In either case, make sure you engine is getting up to temperature. Then check the controls for the blend air door or water control valve function. If memory serves me correctly, no vacuum is used and all controls are electric. Then check the heater core for flow.

Richard

I'd replace that valve with a manual shut off valve commonly available at auto stores.

I had a similar problem with our previous mh. The electric water control valve was bad. That was back in 2004. I found out that there had been problems with that valve during that time frame. In fact the replacement didn't work. The second replacement did. Price was about $100 back then for the valve.

To see if you are getting hot water to your heater core. Start your engine and get it up to operating temps. Locate the inline valve on one of the hoses going to your heater core. Turn the temp up to max. Go out and check temp of each hose on each side of the valve. Both hoses should be warm to hot. If not unplug the electrical connection on the valve a check for 12v. No 12v then the valve is bad.

Mine takes FOREVER to spit out warm air. I talked to my rv tech about it, he told me "it's not like your car" when I told him there must be something wrong with the temp dial. He told me to turn it to hot and leave it there - it will send out warm air eventually. If I have used the block heater prior to starting - much faster to get warm air.

I,d start at the fuse box.

Check cable or vacuum operated valve on line from engine to dash heater core. If you have motor-aid water heater, turn its valve OFF to send all hot water from engine to the dash.

Maybe run your furnace meantime.