MomentumE55

2004 E55 120,000 miles. Once or twice a week when I start the car within a few seconds a kinda loud scary pop or crack sound is heard from right side area of dash sounds rather far in. I searched forums and found talk about stepper motor arms or brackets but they all referred to 8 or so clicks that happen EVERY time car is started, not just one loud one. I realize I will have to disassemble quite a bit and am up for it but would like to know what I am looking for when I do.

E55Greasemonkey

Mine does the same. The 211 does not make the multiple click sound like the C class does. I haven't taken my dash out yet, but suspect its the RH defrost stepper motor arm, or more commonly, the case stop is broken. If it's the case, normally the heater case assembly needs to be replaced, but I think there may be ways to fix it without pulling the heater case out. You will still have to remove the upper dash though.

MomentumE55

Forgot to mention I have 3 irregular shaped 3" circles of condensation that form at base of windshield on passenger side with AC on suspect bleed through of cold air to defroster

stockC43

Mine does it too. Only when it's above 70* or so outside and it's been sitting in the sun. One pop about 3 seconds after starting the car. Haven't really cared enough about it to go any further into diagnosing it. I think it may be the case stop though.

E55Greasemonkey

Same here.

Efivehundred

I had the same issue with my E500. Dealer said the case stop was broken. They replaced the case under CPO warranty. 8 hours of labor on the invoice, if I remember correctly.

ssigarto

In most cases, the whole dashboard has to come out, so 8 hrs is not an unreasonable.