Noisy Air Conditioner ?? Stepper Motor Replacement / Clicking & Hissing
#1
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Thread Starter
Noisy Air Conditioner ?? Stepper Motor Replacement / Clicking & Hissing
![Confused](https://mbworld.org/forums/images/smilies/confused.gif)
Well, my 02' C230k coupe just hit 95,000 mi and it looks like I got my first problem.
![EEK!](https://mbworld.org/forums/images/smilies/eek.gif)
Thanks
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minaflores (04-18-2023)
#2
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My guess....
The sound you are hearing is a vacuum leak on one of the hoses that operate the gating valves that direct the HVAC output. Remove the panels under the dash and look/listen while its in operation. Direct airflow to different parts of the cabin to see if you can pinpoint it. If the evaporator was leaking that bad you'd smell the AC gas and there would be no AC. 98K miles and this is your first problem!!! You have to be very lucky
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#3
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C55 ///AMG, 535xi
this also happened to me. i bought my car in for service and after that i heard that. the SA told me its fine, would go away. i hear it maybe once a week now. but def gonna bring it back tot he dealers.
#4
Senior Member
Thread Starter
Thanks, I don't think it's as simple as just a hose although I hope so. The shhh sound too high a pitch to be just air blowing out a hose. I think it may even occur when the compressor for the AC turns on every so often. I'll check more out this weekend
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#6
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Thread Starter
Ok, It's been a few weeks now since I posed this thread. The shhhh sound went away and now I have a bigger problem. Now when I start the car and its cold there is some ticking in the dash, at the same time the fan in there starts to speed up but then gets knocked back to a slow speed, then speeds up and gets knocked back again. It does this about 10 times or so. In addition I have lost all air to the floor. Even once the car is warmed up and I select just floor air with max fan, from the control, i can hear the fan blowing at max.. but no air is blowing on the floor. My feet have been cold up here for a few days now!
Ok, so question is: Does anyone have experience with this? Is there maybe a simple stripped gear or valve that I can get at from underneith the dash to change? Or is this going to need a professional to take the whole dash off?
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#7
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'01 C320 SS
We may be having the same problem. When I turn on the full auto feature, can hear a loud hissing sound that didn't go away after 3 minutes, so I turned it off... My wife wants me to take it in today, but I'm really not keen on finding out the it's a 2k+ fix, esp. after our extended warranty has expired. Please post your findings.
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#11
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Something Slow
Ok, It's been a few weeks now since I posed this thread. The shhhh sound went away and now I have a bigger problem. Now when I start the car and its cold there is some ticking in the dash, at the same time the fan in there starts to speed up but then gets knocked back to a slow speed, then speeds up and gets knocked back again. It does this about 10 times or so. In addition I have lost all air to the floor. Even once the car is warmed up and I select just floor air with max fan, from the control, i can hear the fan blowing at max.. but no air is blowing on the floor. My feet have been cold up here for a few days now!
Ok, so question is: Does anyone have experience with this? Is there maybe a simple stripped gear or valve that I can get at from underneith the dash to change? Or is this going to need a professional to take the whole dash off?
![Frown](https://mbworld.org/forums/images/smilies/frown.gif)
when its cold out i also get a ticking sound within the dash board it stay ticking for like 5-10 mins and thats without even starting the car.
#12
Senior Member
Thread Starter
Clicking in dash
Ok, well the car is at the shop today. When i brought it in the tech said it is most likely a stepper motor gone bad. That would explain the clicking and the fact i cant get air to the floor. Said they take the bottom off of the dash and get in there (about 4 hours). He estimates $400 - $500. As for the hissing sound maybe its related somehow, maybe not. I don't use the AC all that much anyway and I'll prob trade it in for one of the new 08' C's when they come out next year (They look sweet).
P.S. Brabus --- this was posed in Jan, now i have 97,000mi
P.S. Brabus --- this was posed in Jan, now i have 97,000mi
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#14
Super Member
The ticking noise is pretty common in the W203 cars.. its from a broken stepper motor linkage between the stepper motor and the left footwell flap. There is a short white linkage in there that breaks since it was poorly designed to begin with. I can easily tell you how to do it if you need help. Takes me about 45 minutes to get them done and thats taking my time. Should take the average guy about 2 hours if you don't know what you are doing, maybe less..
Also, the loud hissing noise is from the A/c expansion valve. Basically it means your a/c system is low on refrigerant since you have a leak somewhere. My guess is that it's leaking somewhere around the Drier or around the A/c compressor itself.
Also, the loud hissing noise is from the A/c expansion valve. Basically it means your a/c system is low on refrigerant since you have a leak somewhere. My guess is that it's leaking somewhere around the Drier or around the A/c compressor itself.
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colinkelly (10-17-2023)
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1959 220S / 1979 230 G / 2002 A210 AMG / 2003 C320 SC / 2004.5 C320 SS / 2005 ML350 SE / 2008 smart
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that just means that whoever does the work on their car should take pictures along the way and include them here on this post.
This is what great threads are made of... It just takes smart people to let us know how to do it, and someone to actually do it and take pics along the way !!
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#18
Super Member
This is for the steady clicking noise in the 2001-2004 C230, C240, and C320 that comes on when starting the car or if you notice that you are not able to get the a/c to blow on the driver's feet or if it will not turn off when adjusted to do so. It can get stuck in either position.
If someone in the Dallas/Ft. Worth area would like me to do this to their car and wouldn't mind me taking their car apart and taking pictures of this process for the other people here, please contact me.
My disclaimer is as follows:
These are just my own personal instructions from my own personal experience. If you can not follow the instructions or do not under stand them, ask questions. If someone else wants to take pictures and send them to me as they are doing this procedure, I will gladly make this alot clearer to the rest of you. Also, I am not responsible for you tearing your dash up or breaking items during the removal or installation of this procedure. If you want to pay me to do this, I will gladly take some $$ in turn for my time and knowledge.
So anyways, here it goes..
Item needed:
(1) Footwell flap linkage kit with 2 linkage arms (will edit with the part# tomorrow)
*Note - 99% of the time you do NOT need the A/c stepper motor*
Tools you will need:
(1) flashlight of some kind
(1) 10mm socket (6 or 12pt)
(1) 3/8" ratchet
(1) 6-12" 3/8" extension
(1) T35 Torx socket (3/8")
(1) T20 torx screwdriver
(1) plastic wedge
(1) flat tip small pocket screwdriver (my most used tool)
1. Get in the driver's seat and turn off the car and the radio. I usually listen to the radio for a few minutes before removing it during the process.
2. Pop open the ashtray lid and empty the ashtray.
3. Use either the plastic wedge or your fingers to grab ahold of the front of the shifter surround trim and gently pull it up. Unplug the connectors from it and remove the shifter knob with it. (set all of this in the passenger seat so you won't misplace anything).
4. With the ashtray open, grab ahold of the front of the other trim piece around the shifter that goes from the ashtray to the cupholder. Pop this trim piece off and set it aside.
5. Next open the cupholder area and reach down inside it with either the small screwdriver or some small but long hook and remove the rubber insert where you would set a second cup/drink. (Most people seem to use this as a trashcan or coin holder). The easiest way is to pry it loose at the rear and reach down inside with your fingers and just pull the insert out.
6. There is a small tab on the cupholder that you need to pull slightly up on to pop it loose and then it just twists out and can be removed and set aside. After this, you will notice 2 small tabs at the front of this section that can be pried loose and you can fold the front half of the cupholder section back exposing (2) of the (4) 10mm screws/bolts you must remove.
7. Open the center console lower area and empty it. Next, remove the lower cloth section mat at the bottom of this area and it will expose the remaining (2) 10mm bolts you must remove.
*****Notice: if you have the rear A/C option, you will need to remove the covers for it and then unscrew the rear a/c blower using the T20 torx screwdriver. Next unplug it and set it aside and then remove the (2) exposed black 10mm bolts.
8. ****Notice - engage the parking brake for you and your vehicles safety. Now you should see the black tab at the right rear of the shifter base. Press it forward and pull the gear selector back into neutral or drive. If you have not engaged the parking brake, do so NOW. Grab the small flat tip screwdriver and gently pry the two exposed tabs on the ashtray and pull the assembly up and out of the way. Also, don't forget to unplug it and then set it aside.
9. There is a small black plastic hump shaped cover under where the ashtray sat. Use your fingers to pull them off and that will expose the T35 screws. Be very careful in this next step to not damage your interior. Using the T35 socket on your ratchet, set it to loosen and turn the screw approximately 90 degrees. Once you start feeling resistance, then you need to stop because that is far enough. If you continue to try to loosen these screws past this point, you will damage the center console. Using the flashlight again, you can look under the a/c controls and you will see or feel (2) screws. Using the T20 torx screwdriver, you should remove them. This will allow you to pop the center console loose and move it back and out of the way. You will not have it completely out of the way, just enough to maneuver around it.
10. Next, look into the center A/c vents on the dash above all the buttons above the radio. On the left side of those vents, you will see small plastic tabs. Using the small flat tipped screwdriver, GENTLY pry the lower tab on each side and why holding it away from its proper placement, rotate the vent up until it completely stops and exposes a thin open slit under the vent. Repeat for the other center vent. Using the flashlight, look under the vents and at each side you will see a small torx screw. Now using the T20 torx screwdriver, loosen both screws but DO NOT remove them. They should be held into place by the A/c vent assembly. However, if they do come completely out, just try to push them back into place or use a small magnet to remove them. Now pop the center A/c vents back into their normal positions. Again, using the small flat tip screwdriver, now GENTLY pry against the top tab pressing away from the side and rotate the vent completely down again exposing a small slit but not on the top side of the vent. Grab the flashlight again and look into this area. You will notice small tabs/slits on the top of the a/c vent assembly on the inside. Grab the small screwdriver again and GENTLY pry downwards on the small section closest to you and at the same time, start pulling the A/c vent assembly out of the dash. Sometimes you have to pull those tabs a bit further down than you would think. Also, if you have the illuminated thumb wheels for the vents, you will now have to unplug this one, but don't forget about it.
11. Again, grab the flashlight and now look under the remaining section of the wood trim around the Radio/Command. You should be able to see a small metal loop on either side. Use one of the screwdrivers to pop each one down but not completely out. Doing this, should release the remaining section of the wood trim around the radio. Unplug each connector, but again, mark or remember where each connector came from. There should be atleast 3 connectors depending on your options.
12. Grab a short stool or sit down on the drivers door sill plate. Take the T20 torx screwdriver and reach up under the bottom side of the dash on the drivers footwell area. You should be able to feel a total of (4) screws straight across. Remove them. Now pop down the plastic cover but do not remove it. This will expose the remaining (1) screw attached to the bottom of the dash. Remove it. Using the plastic wedge, pry off the side cover to the dash where the drivers door would meet the dash. There will be a few more screws, remove them. Take the gear shifter and place the vehicle back into PARK. Pull the E-brake handle out to release the brakes and you will find another screw under there but above the handle, remove it. There will be a small metal tab on the side of the Light switch, press it in and remove the light switch after unplugging it. This will expose anther (2) screws in the top of this opening. Pulling out the E-brake release handle again, you can pop the cable loose, but PLEASE take care in how this fits on. Now taking the small flat tipped screw driver or the special tool to remove the plastic ring around your Ignition switch, Carefully do so. Again, I take no responsibility for you scratching up your own interior.
13. Back to the radio area. Take the torx screwdriver and remove all remaining screws from around the radio and dash pieces in this opening. If you have followed the directions up to this point, you will have (9) screws remaining. Remove them all. At this point, you will be able to pop the lower dash section under the instrument cluster/steering column area down and out of the way.
14. Now open the glovebox and there will be a small section of dash remaining between the glovebox opening and the large opening where the radio used to be. You should be able to pry up one of the exposed edges by where the radio used to be and sharply but not too strongly, pop this section loose and away from the dash.
15. By doing this, you can now remove the vents on each side of the center console and set them aside. They are long black plastic air tubes. Now taking the flat tipped screwdriver (you may need a slightly larger/longer one), you can pop the two tabs that hold the black cage to the dash support. Remove it and set it aside.
16. Now if you are in a well lit area, you can see the A/c stepper motor now exposed behind the inner dash support/brace on the left side. Picture where the radio was and now look up and left of it and behind the brace. It is held in place with (3) small silver screws and has the broken linkage between it and the main A/c / heater case. Remove the screws and you should be able to maneuver it around and unplug it. Remove it and you will find that the linkage is either cracked where it connects to this stepper motor or will have fallen off already and shown you what was wrong.
17. After reinstalling everything, and getting everything back together, make sure you have no extra screws and that everything is functioning as normal. To normalize the A/c stepper motors, hold down the Recirc and Front windshield buttons for about 10 seconds or until they both start flashing back and forth. When they are done flashing and you have confirmed everything is working, you are done.
I have a few spare linkage arms at my work and really have no use for them. If I remember correctly, the kit for the 2 linkage arms is about $30. If you would like one, how about $8 each shipped inside the USA. I can also do this entire procedure in less than an hour if you need someone to take care of this for you and you live somewhere in the DFW or Houston area in Texas. Contact me if interested in either.
Also, I may have forgotten a few small details so I will continue to re-read this and go over it in my mind to make sure it is all there. If you have done this before or just notice that I missed something, please let me know.
**** Moderation Edit ****
krazzdav put together a PDF with the write up and all of the pics compiled with each other.....enjoy!!! Unfortunately had to split it up into 3 files to post here.
W203 Air Conditioner Stepper Motor Repair P1 of 3.pdf
W203 Air Conditioner Stepper Motor Repair P2 of 3.pdf
W203 Air Conditioner Stepper Motor Repair P3 of 3.pdf
If someone in the Dallas/Ft. Worth area would like me to do this to their car and wouldn't mind me taking their car apart and taking pictures of this process for the other people here, please contact me.
My disclaimer is as follows:
These are just my own personal instructions from my own personal experience. If you can not follow the instructions or do not under stand them, ask questions. If someone else wants to take pictures and send them to me as they are doing this procedure, I will gladly make this alot clearer to the rest of you. Also, I am not responsible for you tearing your dash up or breaking items during the removal or installation of this procedure. If you want to pay me to do this, I will gladly take some $$ in turn for my time and knowledge.
So anyways, here it goes..
Item needed:
(1) Footwell flap linkage kit with 2 linkage arms (will edit with the part# tomorrow)
*Note - 99% of the time you do NOT need the A/c stepper motor*
Tools you will need:
(1) flashlight of some kind
(1) 10mm socket (6 or 12pt)
(1) 3/8" ratchet
(1) 6-12" 3/8" extension
(1) T35 Torx socket (3/8")
(1) T20 torx screwdriver
(1) plastic wedge
(1) flat tip small pocket screwdriver (my most used tool)
1. Get in the driver's seat and turn off the car and the radio. I usually listen to the radio for a few minutes before removing it during the process.
2. Pop open the ashtray lid and empty the ashtray.
3. Use either the plastic wedge or your fingers to grab ahold of the front of the shifter surround trim and gently pull it up. Unplug the connectors from it and remove the shifter knob with it. (set all of this in the passenger seat so you won't misplace anything).
4. With the ashtray open, grab ahold of the front of the other trim piece around the shifter that goes from the ashtray to the cupholder. Pop this trim piece off and set it aside.
5. Next open the cupholder area and reach down inside it with either the small screwdriver or some small but long hook and remove the rubber insert where you would set a second cup/drink. (Most people seem to use this as a trashcan or coin holder). The easiest way is to pry it loose at the rear and reach down inside with your fingers and just pull the insert out.
6. There is a small tab on the cupholder that you need to pull slightly up on to pop it loose and then it just twists out and can be removed and set aside. After this, you will notice 2 small tabs at the front of this section that can be pried loose and you can fold the front half of the cupholder section back exposing (2) of the (4) 10mm screws/bolts you must remove.
7. Open the center console lower area and empty it. Next, remove the lower cloth section mat at the bottom of this area and it will expose the remaining (2) 10mm bolts you must remove.
*****Notice: if you have the rear A/C option, you will need to remove the covers for it and then unscrew the rear a/c blower using the T20 torx screwdriver. Next unplug it and set it aside and then remove the (2) exposed black 10mm bolts.
8. ****Notice - engage the parking brake for you and your vehicles safety. Now you should see the black tab at the right rear of the shifter base. Press it forward and pull the gear selector back into neutral or drive. If you have not engaged the parking brake, do so NOW. Grab the small flat tip screwdriver and gently pry the two exposed tabs on the ashtray and pull the assembly up and out of the way. Also, don't forget to unplug it and then set it aside.
9. There is a small black plastic hump shaped cover under where the ashtray sat. Use your fingers to pull them off and that will expose the T35 screws. Be very careful in this next step to not damage your interior. Using the T35 socket on your ratchet, set it to loosen and turn the screw approximately 90 degrees. Once you start feeling resistance, then you need to stop because that is far enough. If you continue to try to loosen these screws past this point, you will damage the center console. Using the flashlight again, you can look under the a/c controls and you will see or feel (2) screws. Using the T20 torx screwdriver, you should remove them. This will allow you to pop the center console loose and move it back and out of the way. You will not have it completely out of the way, just enough to maneuver around it.
10. Next, look into the center A/c vents on the dash above all the buttons above the radio. On the left side of those vents, you will see small plastic tabs. Using the small flat tipped screwdriver, GENTLY pry the lower tab on each side and why holding it away from its proper placement, rotate the vent up until it completely stops and exposes a thin open slit under the vent. Repeat for the other center vent. Using the flashlight, look under the vents and at each side you will see a small torx screw. Now using the T20 torx screwdriver, loosen both screws but DO NOT remove them. They should be held into place by the A/c vent assembly. However, if they do come completely out, just try to push them back into place or use a small magnet to remove them. Now pop the center A/c vents back into their normal positions. Again, using the small flat tip screwdriver, now GENTLY pry against the top tab pressing away from the side and rotate the vent completely down again exposing a small slit but not on the top side of the vent. Grab the flashlight again and look into this area. You will notice small tabs/slits on the top of the a/c vent assembly on the inside. Grab the small screwdriver again and GENTLY pry downwards on the small section closest to you and at the same time, start pulling the A/c vent assembly out of the dash. Sometimes you have to pull those tabs a bit further down than you would think. Also, if you have the illuminated thumb wheels for the vents, you will now have to unplug this one, but don't forget about it.
11. Again, grab the flashlight and now look under the remaining section of the wood trim around the Radio/Command. You should be able to see a small metal loop on either side. Use one of the screwdrivers to pop each one down but not completely out. Doing this, should release the remaining section of the wood trim around the radio. Unplug each connector, but again, mark or remember where each connector came from. There should be atleast 3 connectors depending on your options.
12. Grab a short stool or sit down on the drivers door sill plate. Take the T20 torx screwdriver and reach up under the bottom side of the dash on the drivers footwell area. You should be able to feel a total of (4) screws straight across. Remove them. Now pop down the plastic cover but do not remove it. This will expose the remaining (1) screw attached to the bottom of the dash. Remove it. Using the plastic wedge, pry off the side cover to the dash where the drivers door would meet the dash. There will be a few more screws, remove them. Take the gear shifter and place the vehicle back into PARK. Pull the E-brake handle out to release the brakes and you will find another screw under there but above the handle, remove it. There will be a small metal tab on the side of the Light switch, press it in and remove the light switch after unplugging it. This will expose anther (2) screws in the top of this opening. Pulling out the E-brake release handle again, you can pop the cable loose, but PLEASE take care in how this fits on. Now taking the small flat tipped screw driver or the special tool to remove the plastic ring around your Ignition switch, Carefully do so. Again, I take no responsibility for you scratching up your own interior.
13. Back to the radio area. Take the torx screwdriver and remove all remaining screws from around the radio and dash pieces in this opening. If you have followed the directions up to this point, you will have (9) screws remaining. Remove them all. At this point, you will be able to pop the lower dash section under the instrument cluster/steering column area down and out of the way.
14. Now open the glovebox and there will be a small section of dash remaining between the glovebox opening and the large opening where the radio used to be. You should be able to pry up one of the exposed edges by where the radio used to be and sharply but not too strongly, pop this section loose and away from the dash.
15. By doing this, you can now remove the vents on each side of the center console and set them aside. They are long black plastic air tubes. Now taking the flat tipped screwdriver (you may need a slightly larger/longer one), you can pop the two tabs that hold the black cage to the dash support. Remove it and set it aside.
16. Now if you are in a well lit area, you can see the A/c stepper motor now exposed behind the inner dash support/brace on the left side. Picture where the radio was and now look up and left of it and behind the brace. It is held in place with (3) small silver screws and has the broken linkage between it and the main A/c / heater case. Remove the screws and you should be able to maneuver it around and unplug it. Remove it and you will find that the linkage is either cracked where it connects to this stepper motor or will have fallen off already and shown you what was wrong.
17. After reinstalling everything, and getting everything back together, make sure you have no extra screws and that everything is functioning as normal. To normalize the A/c stepper motors, hold down the Recirc and Front windshield buttons for about 10 seconds or until they both start flashing back and forth. When they are done flashing and you have confirmed everything is working, you are done.
I have a few spare linkage arms at my work and really have no use for them. If I remember correctly, the kit for the 2 linkage arms is about $30. If you would like one, how about $8 each shipped inside the USA. I can also do this entire procedure in less than an hour if you need someone to take care of this for you and you live somewhere in the DFW or Houston area in Texas. Contact me if interested in either.
Also, I may have forgotten a few small details so I will continue to re-read this and go over it in my mind to make sure it is all there. If you have done this before or just notice that I missed something, please let me know.
**** Moderation Edit ****
krazzdav put together a PDF with the write up and all of the pics compiled with each other.....enjoy!!! Unfortunately had to split it up into 3 files to post here.
W203 Air Conditioner Stepper Motor Repair P1 of 3.pdf
W203 Air Conditioner Stepper Motor Repair P2 of 3.pdf
W203 Air Conditioner Stepper Motor Repair P3 of 3.pdf
Last edited by awiner; 10-11-2012 at 11:08 PM.
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#20
Senior Member
Thread Starter
Awwww damn I'm too late.
Sh*&! I would have followed this too but I already took the car in. It did end up being the stepper motor and some control flap. Stepper motor was ~$80 and the flap $20. Complete repair cost at Wagner motors here in MA was $500 ! The AC is still making a hissing sound. Wonder how much it is to recharge it?
#22
Super Member
this hissing noise does not mean that you for sure have a leak, but I'd recommend someone to atleast look at your a/c system (lines, compressor, condenser) and make sure there are no leaks.
If the refrigerant charge is low, it had to go somewhere right?..
If the refrigerant charge is low, it had to go somewhere right?..
![nix](https://mbworld.org/forums/images/smilies/nixweiss.gif)
#24