While minding my own business driving to work, I had my climate control set to the warm side of blue. Suddenly, the thing started blowing full hot at the same time. I could tell the air conditioner was blowing cold along with all the warm air. It's like the valve that regulates the warm water just moved fully open.

I stopped the car and turned it all off. Then, I turned the settings to all cold and the system blew cold air only again. AHH!.

If I moved the temp a little warmer, say to white, it will work as normal for about five minutes then blow hot again.

What do I do to fix this mess?

 

Could be the climate control unit. Its self-contained and right there in the center console. Replacement is cheap and simple. Let me know if you'd like to pursue this course and I'll post instructions.

Hope this helps,

 

Replacement is cheap? (how much? and where do I get one cheap?). How do I test the unit to eliminate other possible causes. And yes, please post R & R instructions . Thanks

 

Hi BikerDrew,
You don't state car type, age etc. It all helps.
I'm sure there is no need to change the complete AC unit. Maybe the post meant just the valve.
However I would suggest this is due to the valve controlling hot water to the AC unit. Looks like it is OK whern it is OFF but is unstable when partly open. Not sure how it is controlled at present since problem could be the valve or the signal to it.
If it is a newer car then it may be electronic. Earlier cars relied more on vacuum.
If nobody else replies I will look further into this for you but I'm away on hol for 2 weeks on Friday. Send me a PM if you're stuck.
Stuart

 

Valve is by default open (full on) HVAC unit in dash controls it and they get dry soldered joints. Reasonably cheap tp replace $300 US new or about $80 2nd hand from a later C or E class. R170 units a lot more expensive yet the same. Only position of rear plug different bit fits ok.

http://www.benzworld.org/forums/r170...highlight=hvac
http://www.benzworld.org/forums/sear...earchid=156792


Bazzle

 

Just picked up the climate control unit from ebay for $20. They don't fail that often, so I suppose demand for them is low.

To Replace:

Remove cup holder by opening, flex it down in the center to release and pull it out.

Remove two phillips screws behind cup holder.

Aim air vents up and remove two screws at the top of each vent housing.

Remove stereo and locate two screws at an angle in stereo hole.

Remove these two screws and carefully pull the console bezel out.

I was able to flex the wiring to the switches sideways and not totally disconnect this, but do what you feel is best. The plugs to the switches are idiot-proof.

There is a plastic clip on either side of the climate control unit. Note the position of the air vent ****, flex the plastic clips and pull it out.

The wiring connector has a lever and clip. Depress the clip, raise the lever and remove the connector.

Reverse this process to install the new one.

I just put the gauges and climate control unit out of a Chrysler Crossfire in mine to update the look of my 98. The whole process was simple albeit time consuming.

Hope this helps,

 

Thanks for the help gentleman! I'll look around for a used unit and do the swap.