604benz

When I try to put the heat on it will only blow cold air out of the vents, any ideas, I read it could be a water heat valve located under wiper motor or circulating water heater pump
Is this a easy DIY, any info appreciated.

alx

It could be many many things. Your car needs to be read and hvac module diagnosed via star/ das. Sorry I cannot be more specific, but there is nothing more to say really ...

JDowney

Same thing happened to me. Brought it to the Dealership, and they replaced the Thermostat under warranty...


Jeff

belarus27

+1 on thermostat

kschiu

Heater control valve is busted

604benz

Well I replaced the change over valve, took me around 2 hours to install, heat is working again.

maniekS500

604bezn - did you replaced this part:
https://www.amazon.com/Mercedes-CL55.../dp/B009PQ7YFE
?
I have S500 (with rear climate control) - ordered this part (by VIN) from dealer and I cannot find this under hood.
Do you have any pictures and can you post them or PM me ?

Have issue - I set 16C (cold) on the read - it sending hot air, set 28C (hot) sending little warm.
p.s. I checked duo-control valve located behind right front whell (replaced it becuase on SD there was an error of this valve - after removal one of valves was damaged) still the same.
Thank you,
Mariusz

GPrime2

Check the coolant first to make sure it's not low, if the level is correct, get it scanned. It could be any number of problems, and throwing parts at a problem before diagnosing it is pretty much always a stupid way of going about it. It's well worth your time even if you're a DIY to pay the dealership a half hour of labor (or an hour or whatever) to have them diagnose it and tell you it needs x part. Then change the part yourself. Saves you time and money in the long run.

604benz

Yes that's the part I changed, it was located under wiper motor.

Here's a link

http://www.benzworld.org/forums/w221...ue-only-c.html