Please help. I have a 2009 Grand Caravan with dual temperature control ***** ..one for the driver and one for the passenger.

I can't regulate the temperature on either side with the heat control *****.

When new...once I reached the desired temperature I am pretty certain I could adjust the temperature up and down by turning the **** to red or blue (without the fan running)

Now however ...the heat and cooling ***** do not seem to work unless I turn the fan on.

It gets too hot....I move the **** to the coolest (blue) setting and I continue to get heat....until I turn the fan on ..then it will cool off.

When it gets too cool I turn the **** back to warm (red) and I get no heat until turn the fan on.

I can not regulate the temperature without a two step process of turning the temperature **** and turning on the fan.

Can anyone help me with this or what needs to be replaced. Thanks

 

Flush the heater core. Common problem on dual zone temp control models.

 

The heating and cooling work fine so I do not think the core is clogged...the problem is that I can not adjust the temperature without turning on the fan. Do you still feel flushing the heater core will solve the problem...the last time I had it in they said i may have to replace the defrost door that is internal to the heater box. Thanks for your reply

 

If the fan is not on, the system is off, so the temperature control ***** will do nothing since no air is moving. For it to operate, the fan has to be on to at least level 1.

 

This. The fan has to be on for the system to work.