2002 Patriot Dash Heater Blowing Cold

[Jack W Hannah]

Tried the dash heater for the 1st time since taking ownership a couple of yrs ago and it's blowing cold. The only work done to this coach since I"ve had it that could possibly be related was replacing the squirrel cage blower and replacing a couple of Hydro Hot hoses that supply the two interior zones.
I'm not familiar with the routing of the hoses that would would feed the heater core for this dash heater system. Some possible pertinent information: 1) The coach is not equipped with Engine Pre-Heat via the Hydro Hot. 2) The coach is equipped with a Hydro Hot HHE - 500. The Hydro Hot manual indicates this model is equipped with the Motoraide feature but I'm not sure how, or if, this works without the Engine Pre Heat option.
Any info regarding the dash heater hose routing or other possible causes would be appreciated.

Thank you.

[Steve Huber Co-Admin]

Jack,
Verify that the vacuum operated heater valve is working. It should be mounted on the outside of the front "firewall". It allows hot engine to enter the dash heating system. If not working, verify the 12v vacuum pump is operational and there are no hose leaks.
Steve

[Fred Brooks]

   Jack,
Not real sure on your 2002 patriot, but most coaches have a shut off valve on the engine suppling hot coolant to the front heater core. It may have been turned off for previous repairs. My 2000 has a 3-way valve just under the engine access hatch between the bed and closet. The "winter" position supplies engine heat to the heater core. Perhaps a fellow Beaver owner of a 2002 Patriot came chime in and be more specific. Fred

[Richard Good]

Your coach is probably similar to mine. If you pull the cover off just below your windshield wipers this will give you access to the heater coil area. To the right of the heater and AC coils is a 3 way valve operated by vacuum from the vacuum pump via the heater/AC/fan control. First check this is working. If not you will have no flow from the engine. If this is OK and you still have no flow, there is a heat exchanger on the passenger side of the engine compartment with some valves. Check the valves are in the correct position or again, you will have no flow to the heater. Hope this helps.