Heater Control not working on dash

[Mr__Coach]

OK, I've diagnosed to the full extend of my knowledge (which is not much) on fixing my heater/ac blower motor on my dash from working only on high. I've replaced the resistor and the relay still only works on high. I've checked wires and fuses, I've checked all grounds, I've followed wires, I've checked power to everything and nothing. I've also noticed that my controls won't change from defrost to vent to floor just stays on defrost. I'm also wondering why this unit turns on even when the key to the ignition is off and even when the unit is turned off the fan will still run if turned on high. I am majorly confused on this, I don't know what else to look for? Only thing I can think of is changing out the entire heater control panel. Any ideas from anyone else? This is really bugging me.. Thanks for any help out there..

[westend]

Have you inspected the contacts on the blower motor. I guess it would be possible that the motor's contacts have shorted and full voltage is always going to the motor.

[Mr__Coach]

Installed a new heater switch. Nothing, same thing. Only works on high...Any ideas?

[Mr__Coach]

Can't believe I forgot to put the make and model in.:S It is a 2000 Ford Chassis on a Damon Intruder 349.

[j-d]

If it's a Class A on Workhorse, we had a case of a stuck relay.

Also, if the vacuum to the mode select "switch" (actually a vacuum switching valve) has failed (broken hose, leaky reserve tank, bad select switch), then the system defaults to Defrost.

We need Make, Model, Year. Chassis year, not RV model year.

[Jim-Linda]

Could you perhaps, list the vehicle you are inquiring about?

Jim