[JimB]

Hi All, Its been a while since my last post on this forum, but anyway last night when my wife got home told me that she was hearing a popping sound when she was backing up. We tried to listen to it but I did not hear anything I said I will drive it this morning if I can hear what she's talking about and good enough as soon as I started the car I start hearing a popping sound by the ignition key. Yes I did check a "search " section but they are all saying they can hear it when turning and suggested its a sway bar bushing need to be lubricated. But on mine I'm not even moving it sounds like a spinning wheel hitting a plastic frame behind the dash under the ignition key. Any idea where that sound coming from? I will check it again tonight when I get home.

TIA
Jim

 

[schumicat]

it sounds like there could be a piece of paper or leaf stuck in the fan that blows air for the hvac system.

 

[JimB]

it sounds like there could be a piece of paper or leaf stuck in the fan that blows air for the hvac system.

I'm afraid this could be the problem, a broken stepper motor activating arm. Its a part of the ventilation system. :-(

http://mbworld.org/forums/c-class-w...per-motor-replacement-clicking-hissing-3.html

 

[rudeney]

Try the climate control test/reset - simultaneously press and hold the RECIRC and FRONT DEFOG buttons until their lights begin to blink. This runs the test procedure which should last 20-30 seconds and then the lights will stop blinking. If they do not stop blinking, then you have a problem with a broken linkage or a bad servo.

 

[JimB]

I will try that right now, my car is in the parking lot.


Thanks
Jim

 

[JimB]

I tried the test/reset that you mentioned and the lights still blinking after about a minute, and still popping even the key is out of the ignition. I guess need to to tackle the dyi/job one of this day.

 

[rudeney]

Get someone with SDS to check the codes (you can't do it with a generic OBDII scanner). The error codes will tell you what it wrong so you don't have to rip the entire dash apart trying to find the problem.

 

[JimB]

Thanks Rudeney,

 

[sunnyray_toronto]

You did HVAC resynch-test and it did NOT stop by itself.
Popping cracking sound occurs when you first start the car,... and it happens about every 5 seconds for about 30-45 seconds.

Sounds like the foot-well control levers,.... about $20,.... Part Number: A203-830-00-33
HVAC Control Lever Kit For Left/Right Footwell Flap Levers Contains: (2) Control Levers

To confirm,.... play with the HVAC,.... change to different settings,... mainly vent settings (foot well, body, window vent, etc,....),.... and temperature setting,... but for each setting use your hands to feel for the air coming out of all the vents,.... and notice which one is open or closed,.... My bet is the foot-well vent is stuck either open or closed all the time,.... regardless of vent setting,.... If so, then you know your foot well vent is broken,.... it`s either foot-well stepper motor or the cheap plastic lever,.... 99% of the time its the cheap plastic lever,....

 

[JimB]

You did HVAC resynch-test and it did NOT stop by itself.
Popping cracking sound occurs when you first start the car,... and it happens about every 5 seconds for about 30-45 seconds.

Sounds like the foot-well control levers,.... about $20,.... Part Number: A203-830-00-33
HVAC Control Lever Kit For Left/Right Footwell Flap Levers Contains: (2) Control Levers

To confirm,.... play with the HVAC,.... change to different settings,... mainly vent settings (foot well, body, window vent, etc,....),.... and temperature setting,... but for each setting use your hands to feel for the air coming out of all the vents,.... and notice which one is open or closed,.... My bet is the foot-well vent is stuck either open or closed all the time,.... regardless of vent setting,.... If so, then you know your foot well vent is broken,.... it`s either foot-well stepper motor or the cheap plastic lever,.... 99% of the time its the cheap plastic lever,....

Hey Sunnyray, Thanks for the new place to look for, I think you might be right becausst it sound like the sound coming from just right on top of the gas pedal.. I was going to take the bottom cover apart this week end but I got side track for some honey do list, but I defiantely will take a look at that.
Thanks again
JIm