SamC43

Hi everyone. I have a c43 and have a problem where the heater is throwing out COLD air when I have the switch to AUTO. I can have it at 70-90 and cold air comes out, very annoying. If I put the switch for the vents to throw air up,down, or straight it throws hot air. But on AUTO it thows cold air.

I want to fix this myself but need some direction/advice as to what it might be causing these?

Thanks in advance!

Z06EATER

looks like a sensor is bad bro....damn i can't remember wat it's called tho maybe someone here can say

DogWagen

This sort of problem has been discussed before but I can't recall the solution - I suggest that you search the forums. Found this one although it is for an E210 https://mbworld.org/forums/e-class-w...wing-cold.html

SamC43

I did do a search but found nothing.....Im thinking it might be that part thats by the passenger side which people clean out when their AC throws hot air. It has the water hose that runs to it and I believe it might have a sensor?

Anyone else have any ideas what this might be?

MarcusF

Signal to Noise has a section on the duovalve. Just scroll down on the left. It doesn't take long, and it's inexpensive to fix. Unless it's actually broken or you break it while trying to fix it. I have no idea what the part number for you car is. It's probably going to be 001830nnnn.

SamC43

Thanks guys! I think the duovalve is the problem. Now I have to see what it costs, Im sure its not cheap.