Heater Control Valve Stuck Open?

[TexasViper35]

Hello All,

My AC was freezing me out one day and then coolish warm the next. It gets cool-cold with the AC on but not like before. We had a very chilly day the other day so I switched off the AC and the recirculating switch but the air coming out was very warm.

I’m wondering what might be the issue. I was suspecting the valve that closes the coolant from the heater, but I really don’t know where to look. Any direction / advice would be sincerely appreciated!

 

[MoparMap]

The Viper doesn't have a coolant control valve like most cars from what I recall. It only uses a blend door in the HVAC box to control the hot vs cold air. On mine the post for the door that sticks through the box that the servo rotates actually sheared off. I don't know if yours has gone that far though. Does moving the temperature dial change anything at all? That servo has a calibration process, it could be that it just lost its memory and doesn't know where full hot and cold are, but if nothing is changing I would bet either the servo died or the door shaft broke like mine.

The bad news is if it is the shaft you have to take the whole dash out to get to it. Not actually as bad of a job as I would have originally thought, but it's reasonably involved and will take some time. Easier on a convertible for sure, just because you have a little more room to work with. I jerry rigged mine back together by glueing the broken piece back on with a screw through the middle for insurance, but it really needs to be replaced one of these days. I didn't want to disconnect the A/C lines to remove the whole box to do that at the time, hence the glue and screw fix.

 

[TexasViper35]

Thank you MoparMap!

I’m not sure why it was blowing hot air (set on fresh air only) on a pretty cool day, but after reading your post I went ahead to check the r134a. It was low, just below the green zone, so I added 1/2 a can and it’s ice cold again.

Thanks again for your expert information.

 

[MoparMap]

Haha, didn't even think about that. Glad you got it figured out though!