Mercedes: Mercedes 2003 E-320 climate control, climate control system, mercedes e 320

Question
QUESTION: the heat just stopped coming out - the blower/fan works but no heat...cannot locate a climate control fuse based on the paper regarding fuses.  What can this be?

ANSWER: Hello Sharon,
It is possible that the mono valve has failed. This electrically operated valve blends water into the climate control system. I recommend that you locate an independent Mercedes mechanic and have them take a look.
Let me know if you have other questions.
Rob

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QUESTION: Another person mentioned a "dual" valve - and needing to have the car put on a star diag system to find a fault code.  Any idea what/where the dual valce is?

Answer
Sharon
The dual valve probably serves the same purpose as the monovalve on earlier models. My monovalve is mounted in a space inside the fire wall. The 420 uses essentially two fire walls.This space between houses lots of things. If you search google for mercedes  e-320 dual valve, you should come up with several sites that sell parts and you will be able to see what it looks like.
One site had dual valves for about 120.00. If you have a dealer ship repair the vehicle I would expect the part to be about twice that price.
This is why I recommend local independent mechanics.
Good Luck
Rob