Hi all, first post here.
I have a 2007 500, with the dual zone automatic climate control.
I'm having intermittent problems with the heater blowing hot air and then cool air. (On cold days) - Which, frustrates my wife (it's her daily driver) to no end. I've not been able to duplicate the problem myself, but it might be because I attempted to do so on a milder day. I've asked her to keep an eye on the engine temp gauge, to see if it changes, but it doesn't. I've asked her to manually turn the A/C on and off, to see if it makes a difference, -it doesn't.
Does anybody have any experience with this?
This is the first and only car that we've ever had, with "automatic" climate control, so, this is uncharted territory for me.
I appreciate any help that you can give me.
Best regards,
Tom

 

Two possibilities come to mind.
If the heater core itself is plugged restricting coolant flow that is one possibility. To check this , warm the engine to operating temp and set the system (both) to max heat setting and feel if the heater hoses both are the same temp. If they are, check them for a few minutes to make sure they both stay hot. They should. If not , there is a good possibility the heater core is restricted which would require flushing or replacement.
One of the other possibilities could involve the control unit and that would require more specific testing to determine if it is sending the right info to the blend doors.

 

Thanks Hanky, I'll give it a whirl!
Tom

 

Thinking that, pretty much everything on this car is run by computers, -the heater control unit incluced, I decided to see if I could re-boot it by disconnecting the battery ground. -We'll see if it works, I ran it for about 20 minutes, dinking around with the heater temp settings and didn't notice anything odd. We'll see if it did the trick...