Noisy Air Conditioner ?? Stepper Motor Replacement / Clicking & Hissing
#28
I just bought a 2003 C320 and it was making that noise after start up. I bought the parts for about $11. I followed your instructions exactly. Everything worked well until I got to the last step where you say to remove the 3 silver screws that hold the stepper motor on and remove it. What I am trying to figure out is how to get to the two screws that are behind the brace. Am I missing something? Is there something else I need to remove first? I don't have any torx tool that will fit in there and still be able to turn the screw out. Any help would be greatly appreciated.
#29
MBWorld Fanatic!
T20....attack the screw heads at an angle...flex the air housing a little with your left hand and it works.
#30
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Join Date: Jan 2007
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2003 C240
Man, those are some amazing instructions, however, I know I would not be able to do it myself. I also have the click noise on startup...It's not too annoying for me yet, I've had the car almost two months...(it had this prob when I purchased it used)....However, I'm still able to sometimes get the heat on the floor to work...I usually keep the vent control right in the middle...and if i need the heat on the floor becuz my feet are frostbiten, i turn up the fan control all the way and then quickly turn the vent control to the bottom...it usually works when I do it quick like that, then I can turn down the fan and have nice heat on my feet. I know I wont be able to do this myself, I'd rather wait until it really bothers me and I have what the stealership wants to steal from me for it
#33
Senior Member
Thread Starter
Hissing noise from AC = low refrigerant
Took my car in last month to have the hissing noise checked. Come to find out it was low refrigerant. They checked the hoses for leaks using the dye and didn't find any. Price for the recharge wasn't all that bad. Just an FYI for anyone else who may be approching 100k miles. You may be needing a recharge in the near future.
#34
Almost a Member!
Racin fool,
Just finished tearing the dash apart last night to get to my broken steper motor linkage and took some pics as I followed your directions! Great directions! I would have never figured out all the hidden bolts and screws without your help!
Want me to email you my pics so you can post them in your directions posting? I shot every step... over 50 pics that you can choose from! Shoot me a PM and I will gladly do that for the Forum!
Saved me atleast $400! Thanks!!!
Robert
Just finished tearing the dash apart last night to get to my broken steper motor linkage and took some pics as I followed your directions! Great directions! I would have never figured out all the hidden bolts and screws without your help!
Want me to email you my pics so you can post them in your directions posting? I shot every step... over 50 pics that you can choose from! Shoot me a PM and I will gladly do that for the Forum!
Saved me atleast $400! Thanks!!!
Robert
Last edited by liveniceguy; 05-17-2007 at 12:52 PM. Reason: Adding pic quantity
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#37
Almost a Member!
Would you believe that after installing the new linkage (yes I did find one broken) and putting the whole car back together that I still have the clicking noise!!!! Grrrrrr
I guess the stepper motor is bad as well. Does anyone know how to check for a bad stepper motor?? I guess I will tear things back apart then plug the a/c controll panel back in and turn the ignition on to identify which stepper motor is clicking. Any other suggestions?
Only good news is that I finally hardwired my Sirius radio and a 3 outlet 12volt block (to run my radar detector and cell phone charger). Finally got my center consol uncluttered!!
I guess the stepper motor is bad as well. Does anyone know how to check for a bad stepper motor?? I guess I will tear things back apart then plug the a/c controll panel back in and turn the ignition on to identify which stepper motor is clicking. Any other suggestions?
Only good news is that I finally hardwired my Sirius radio and a 3 outlet 12volt block (to run my radar detector and cell phone charger). Finally got my center consol uncluttered!!
#38
MBWorld Fanatic!
I took my stepper motor apart when I had it out just to look at it....just push in some captive plastic pins on the cover and it comes off (don't loose the spring & washer in there!) Not much to it that could break unless one of the wires came off but then I think you would get no sound, no action at all. Did you take off the arm on the right side foot well and look at it? The arm that I replaced on the left side didn't appear broken until I looked at it real close and there was a crack that allowed the stepper motor shaft to slip inside of it - that was the clicking sound. Also, did you move the vent actuator arm by hand to see if it had free travel to both extremes?
#39
Almost a Member!
I did check the movement of vent that the bronen linkage was attached to. The clicking is coming from the same location as before, right behind the left side of the radio/ ignition area (up high in the dash). If the clicking is there should I still check the right side foot well. Are you talking the passanger side of the car? Or the accelerator side of the dash panel?
The two pics below shows the broken linkage and the stepper motor placement that I am refering to.
Thanks!
Robert
The two pics below shows the broken linkage and the stepper motor placement that I am refering to.
Thanks!
Robert
Last edited by liveniceguy; 05-18-2007 at 02:00 PM. Reason: added info...
#40
Almost a Member!
UPDATE....
Tore into the Benzo for the last time to find the clicking in the dash. Here are the results....
2nd time taking things apart about 30 mins! Once I got down to the stepper motors I hooked the radio trim panel with climate control back to the car. Turned on the ignition and realized the stepper motor right behind the radio was clicking. Unscrewed it and left it plugged in. Turned on the ignition again and the motor turned freely. I was puzzled. Everything that it connects to spins freely. I decided to switch two stepper motors and found that the same motor clicks. Took it back off and put a linkage lever on it and twisted. One direction it sounded like a standard servo motor. The other direction it made a clicking noise!! Ahhh haaa. Gotcha! Stepper motors do click!!
Stealership has one in stock. Part #A203 820 16 42. $104 before taxes. Looks like all the stepper motors have the same part number. I would have bought one upfront to replace it right away but they have a no returns policy on electronic parts. I figured I would diagnose it first.
So in summary.....
Tear everything apart. Plug the climate control panel back in. Turn on ignition. Touch each stepper motor to identify which is clicking. Pull motor to see if the linkage is broken. Turn motor each direction with linkage to see if motor makes a clicking noise.
I found one linkage broken behind the left hand center dash brace stepper motor and one broken stepper motor directly behind the radio.
Make sure you check everything out before you reassemble. I found the one broken link and assumed that it was the only problem. Lost a couple of hours putting things back together only to find that a stepper motor was also bad!
Going to the stealership tomorrow to get a new stepper motor.
Will post pics of the process soon....
Robert
P.S. The wifey now calls me the east coast SMK (stepper motor king). lol
Tore into the Benzo for the last time to find the clicking in the dash. Here are the results....
2nd time taking things apart about 30 mins! Once I got down to the stepper motors I hooked the radio trim panel with climate control back to the car. Turned on the ignition and realized the stepper motor right behind the radio was clicking. Unscrewed it and left it plugged in. Turned on the ignition again and the motor turned freely. I was puzzled. Everything that it connects to spins freely. I decided to switch two stepper motors and found that the same motor clicks. Took it back off and put a linkage lever on it and twisted. One direction it sounded like a standard servo motor. The other direction it made a clicking noise!! Ahhh haaa. Gotcha! Stepper motors do click!!
Stealership has one in stock. Part #A203 820 16 42. $104 before taxes. Looks like all the stepper motors have the same part number. I would have bought one upfront to replace it right away but they have a no returns policy on electronic parts. I figured I would diagnose it first.
So in summary.....
Tear everything apart. Plug the climate control panel back in. Turn on ignition. Touch each stepper motor to identify which is clicking. Pull motor to see if the linkage is broken. Turn motor each direction with linkage to see if motor makes a clicking noise.
I found one linkage broken behind the left hand center dash brace stepper motor and one broken stepper motor directly behind the radio.
Make sure you check everything out before you reassemble. I found the one broken link and assumed that it was the only problem. Lost a couple of hours putting things back together only to find that a stepper motor was also bad!
Going to the stealership tomorrow to get a new stepper motor.
Will post pics of the process soon....
Robert
P.S. The wifey now calls me the east coast SMK (stepper motor king). lol
Last edited by liveniceguy; 05-18-2007 at 11:58 PM. Reason: more narrative
#41
MBWorld Fanatic!
Don't forget to resync.....
"To resync the flaps press the defrost and recirculate buttons at the same time. The flap will cycle for up to 30 seconds then stop. If they keep cycling for longer than 30 sec it means they cant all sync due to a faulty stepper motor or linkage." (from another post). Also....take the bad motor apart and see if there's anything obvious broken. Good information.
#43
Almost a Member!
Pics of the process (some pics were taken out of order and you may still see trim pieces on that were already taken off in prior steps)....
Last edited by liveniceguy; 05-22-2007 at 04:55 PM. Reason: Remove Txt..
#48
Almost a Member!
Step #11...
Additional comments for step....
If you pull the radio trim off before you remove the ash tray, place tape on the ash tray lid to protect the finish from screwdriver scrapes (as shown with the green tape).
Additional comments for step....
If you pull the radio trim off before you remove the ash tray, place tape on the ash tray lid to protect the finish from screwdriver scrapes (as shown with the green tape).
Last edited by liveniceguy; 05-22-2007 at 04:57 PM. Reason: Added Txt.
#50
Almost a Member!
Step #12 (cont)...
Additional comments for step....
The plastic ring around the ignition switch rotates counter-clockwise and spins off the threads on the switch.
Additional comments for step....
The plastic ring around the ignition switch rotates counter-clockwise and spins off the threads on the switch.
Last edited by liveniceguy; 05-22-2007 at 05:00 PM. Reason: Added txt.