QWKSNKE

Has anyone cleaned this? Mine started making a noise today and from I have read it appears a good cleaning needs to be done as the cars get older.

Anyways, I haven't found a good write up or video on a proper way to do this.

Plutoe

Wada you mean noise and where did you ever read in any MB repair service\document that the sensor needs to be cleaned!!

zcct04

Where did you ever read in the OP's post that a sensor needs to be cleaned?

m a x i m u s

I didn't even know we had a fan there.

Arjy

same, i've poked around in the dome assembly for when i was hardwiring my valentine one, and dont remember seeing any sort of fan. but i definitely was not looking for one either!

QWKSNKE

Yeah I never knew there was one in their either until searching the net yesterday on what the noise was I was hearing.

If you look towards the front of the dome light assy you will see the holes that kinda looks like a speaker cover. This is the inlet for the fan that pulls in air to the sensor that measures the temp of cabin air to run the climate control system.

If I don't pull it down this evening, I will tomorrow and post pics of disassembly and cleaning.

QWKSNKE

ok. So I went ahead and disassembled the light this evening. AND I was incorrect on the placement of the fan (or air sniffer as some call it) On the W204 it is at the rear of the dome light assy. not at the front like earlier model platforms.

Also, based off an experience I went through last year when the headliner was removed, I advise that you DO NOT turn on the ignition at any time while the dome light assy is unplugged. This could lead you to needing a STAR program reset.

Before getting into pic definitions, the purpose of this disassembly is to expose the fan where you can hit it with low pressure air and/or q-tip with alcohol for cleaning.


See this video for dome light removal


PIC 1- This is a connector I could not get unplugged for complete removal. Lets call this the P.I.A connector

PIC 2 - Back of dome light assy

PIC 3 - Green Arrows pointing to all screws to be removed. Red arrows reflect special notes.

PIC 4 - This is the dome light assy with the back and circuit card removed..Green arrow points to fan inlet

PIC 5 thru 7 - Various shots of the fan motor on the CCA. Notice all the crud. You might be able to see a dead bug in one of the pics. There was one there that I suspect may have caused the noise I heard yesterday before flying out of the fan.

I did not take pics of the connectors that should be unplugged. IT is assumed that anyone taking on this task has enough sense to unplug them

m a x i m u s

Interesting! Thank you for the pics.

Arjy

thanks for the pics. way smaller than i expected!

shamrode

I have an 09. Does it have that fan? What is the purpose of the fan?

QWKSNKE

Yes the fan pulls in air to measure cabin temp so that your climate control knows how cool or warm it needs to be putting out

chrisridebike8

I think mine is making noise too. At first I thought it might be my diff, but I hear the noise when stationary so I'm thinking it's this fan.