I have no control over the temperature coming out of the interior vents on my 2005 SRT CONV. Even with the AC on all I get is very hot air. Fan speed control works as well as vent selector. I've tried varying speeds and temp selection but no luck.
With politicians I just change channel but would like to fix this hot air problem. Any and all help is GREATLY appreciated.

 

Freon may need recharged. Is the compressor kicking on?

 

Hi Bill
Not really sure how to tell if the A/C is kicking or not. Would the lack of freon cause it not to blow cooler air even with the A/C off? In my searching the forum I read something about individual vents that control air flow not working but nothing really specific.
thank you!

 

To check if the A/C Compressor is engaging, you'll need to open the hood and locate.

You will see it as one of the components of the Fan Belt system.

When you turn on the A/C, typically you will hear the Compressor click, as the clutch engages, and pulls in the assembly for operation.

Assuming you can find it, and it appears to engage, but no cold air, next step is to assume a Freon leak.

Best bet is a local A/C shop, they can check if Freon present, and insert dye into system to locate leaks.

Before you get ripped off on price for possible Compressor or Condenser, check here first, they'll help keep the pricing honest...

 

Sounds like either a changeover valve or possibly the air-blend door not moving to the correct position. I have seen very few failures of the A/C system itself on these cars (SRT6 & SLK's back to 1998). I know mine gets stuck in heat only mode on occasion. Since I have my center console out, I will try to run down the cause (probably this weekend). I will update you if I find some better info. In the meantime, the following is the description from the service manual:
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In a blend-air system, a blend door controls the amount of unconditioned air (or cooled air from the evaporator) that is allowed to flow through and around, the heater core. A temperature control on the A/C heater control panel determines the discharge air temperature by energizing the blend door actuator, which operates the blend door. This allows an almost immediate control of the output air temperature of the system.

The mode control on the A/C heater control panel is used to direct the conditioned air to the selected system outlets. The mode control uses engine vacuum to control the mode doors, which are operated by vacuum actuators.

 

It happend to my SRT6 about one month ago. No matter what I did only hot air would come out - not a good situation in Florida. I quickly brought it over to the certified Crossfire mechanic at the local dealer. He had never seen this before so he contacted his help line. They told him to first try reloading the computer. He said there were many odd communications error codes in the system and after he reloaded the code it has been working fine.

 

thank you for the suggestions. will post the fix as soon as work slows down and have some time to take a closer look or take it to the shop

 

Did you fix it? Mine is doing this.

 

I do not think the A/C is involved. I turn the A/c switch off or on. And I have HOT air at every vent. Even with A/C turned off I should have cool air from the vents if outside temp is cold and fan switch on. The hot air is only there if the fan switch is on. My Temp setting makes no difference with A/C on or off. The air blind door must be working as no air comes out if the fan switch is off. I plan to check the Coolant circulation valve today. I THINK that the AIR blind door would be Vacuum controlled and the coolant circulation valve is electrical controlled. But that is just my guess.

 

Finally fixed my issue of only blowing hot air. Whether the temp controls were on blue or red it would only blow hot and no AC. What I did was take the aluminum caps off the coolant circulation valves which are located directly behind the overflow tank, careful not to drop any of the 5 screws. After lifting the caps off I lifted the yellow wrapped magnets off of the valves, which is one piece and then cleaned the base that the magnets sit on. I pulled the valves out careful not to lose the springs sprayed them with a lubricant and reinstalled. Put everything back together and now I have AC and control of my cabin temps.

 

I can't thank you enough, I printed this info and took car to AC shop. he was skeptical but did it $20.00

 

what kinda lubricant is used?

 

That is awesome to know. Thanks for posting the cure. I would have been digging around looking for the blend door actuator as I've had that fail in another car and when it does it seems to fail stuck in the full HEAT position directing all air through the heater core.

 

what kinda lubricantwas used?

 

I believe this is the problem with mine, I’m going to try and clean it before replacing it

https://www.autohausaz.com/pn/14401715-0018307784?utm_source=google&utm_medium=cpc&utm_ca mpaign=feedmobile_Mercedes&gclid=CjwKCAjwgb6IBhARE iwAgMYKRjbTK9VswBNzzjspRUqCFoh5i-m1Iv-U9jcrYeqE_j3XyB5Y3v4WBRoCGm0QAvD_BwE&fbclid=IwAR2Y _6hUS8nBMUptM6e2Vwi2SCYS0AHksLOSai4qOtLzHddEltfwkC 7SXak

 

IF that runs into a problem (cleaning or very dirty or cut gaskets), this ( https://www.ebay.com/itm/223941503226?hash=item3423f428fa:gEIAAOSw2aJeZqo- ) might be the answer. Of course, make sure your coils are intact (ohm them out) and the seating surfaces for the gaskets aren't nicked/cut. Good luck!