Dash Temperature Control: Hot or Cold, no inbetween

Apparently no one ever told Ford Trucks how to build a temperature control that works. Mine have all been the same way, either on or off, no in between.

The cockpit control sends an analog signal to the flapper valve control module. If this module (forward of the firewall) has ever been subjected to moisture (as in condensation etc) it will corrode and fail to operate the flapper valve correctly.

You might install a manual water cut-off to your heater core. That may also give you colder a/c in the summer.
It helped my '04' Newmar WH chassis.

hikerman wrote:
You might install a manual water cut-off to your heater core. That may also give you colder a/c in the summer.
It helped my '04' Newmar WH chassis.

true sometimes when using AC only but OP is trying regulate the cabin air temp while in heater mode.sounds like the controll switch sends too much vacuum to the control module and its either closed or open and not staying part way

One option is operator understanding error

There are basically 3 types of temp controls

one restricts water flow in the heater core
One mixes air that passes through the heater core with air that bypasses the heater control

and one::::: IS an actual thermostat that will switch between "VENT" (cold) and "HEAT" (heater) as needed.

Gallifrey wrote:
Hi,

Now that it's a bit chillier, I've noticed the temperature control knob on my dash is almost either full-on hot or full-on cold. There's a few degrees where I can adjust it between the two, but it's only a few degrees of the full rotation of the knob and it's impossible to get the temperature just right.

Any suggestions on what might be wrong? I'm fairly handy and willing to fix things, but I don't know where to start when it comes to the dash climate control system.

I have a 2011 Winnebago Itaska 32K which has a Ford chassis.

Thanks for any help or suggestions.

most likely you have a ambient air temp control system. the sensor may be bad.

I have an old Ford that started doing this and it's because the foam around the blend doors has dried up and gone away.

Johno02 wrote:
Apparently no one ever told Ford Trucks how to build a temperature control that works. Mine have all been the same way, either on or off, no in between.

NO Class A motorhome has a FORD/Chevy AC/Heater system. They are ALL aftermarket add on systems. The problem the OP is experiencing is normal. Class A Motorhomes do NOT use the blend door systems Automobiles use that regulates the Hot and Cold to a even set temp. While the Temp control does rotate. the problem is simple, once the valve is even slightly opened to allow Hot water thru the Heater Core, it only takes less than 15 minutes for that heater core to get to the Engine Coolant temp(usually around 185 degrees). With NO blend door system, that means the output of air will be HOT and not lukewarm like you would like it. Doug

I have a similar issue. I replaced my mechanical heater valve with an electronic controlled valve. The ID of the new valve is smaller, and any attempt to throttle the flow forces the flow through the heater bypass built into the piping. My solution will be to buy a 4 port control valve and eliminate the bypass.

dougrainer wrote:

Johno02 wrote:
Apparently no one ever told Ford Trucks how to build a temperature control that works. Mine have all been the same way, either on or off, no in between.

NO Class A motorhome has a FORD/Chevy AC/Heater system. They are ALL aftermarket add on systems. The problem the OP is experiencing is normal. Class A Motorhomes do NOT use the blend door systems Automobiles use that regulates the Hot and Cold to a even set temp. While the Temp control does rotate. the problem is simple, once the valve is even slightly opened to allow Hot water thru the Heater Core, it only takes less than 15 minutes for that heater core to get to the Engine Coolant temp(usually around 185 degrees). With NO blend door system, that means the output of air will be HOT and not lukewarm like you would like it. Doug

that may be I never really looked. I do know my heater on my sparton chassis responds very well to heater /ac temp control changes
as it should,