HELP - AC Fan Cuts On & OFF - Have ALREADY TRIED the Blower Reg Swap-Out :-(
OK - I have a 1999 E430 that is my wife's car - AC Fan starts up when the car gets started, works for about 2 minutes - THEN - ALL FAN ACTION stops - NO cool air - NO hot air - NADA-ZIP-BUPKISS!!!!
I have ALREADY replaced:
Fan Blower Motor Assembly - newer 1999 and up version with PLASTIC frame - not metal
Blower Motor Regulator - newer 1999 and up version
I have already PURCHASED the S-Class blower motor regulator that ONLY WORKS WITH THE "OLDER" VERSIONS OF THE FAN/BLOWER - I cant use this part (that I bought for around $165.00 based on all of the glowing feedback from others here) - TOTAL WASTE for my own situation here in Phoenix, AZ, USA
Here's my Dilema - The fan cuts out after a couple of minutes, then cuts on for about 30 seconds and cuts off again - this happens now whenever the car is driven.
My Climate Control Unit shows a "partial" letter "F" on the far right side of the display (it looks like a backwards 7)
Is my CCU bad? or do I need to look at other factors?
monitor the signal voltage on the yellow wire should be between about 1,5 to 6v depending on fan speed setting, if the voltage remains constant when your fan stops, then the fault is not your controller, when it stops bridge the brown and blue if the fan runs at full speed your regulator is faulty
The fan totally stops - no wind, not cool, no hot - no air flow at all - then, all of a sudden, the fan will start up again, and you have nice, cooled air for about... 45 seconds, then it fades quickly - like it's being shut down with a "dimmer switch".....
The display on the ACC is failing -- you are loosing parts of the liquid crystal -- it should look like the other "F" but the missing segment is not working. I don't ever remember hearing that this is a cause of concern as to the workings of the system -- it just becomes impossible to work the system if you loose too many segments.
Since the system is working initially -- the climate control must be sending a signal. You need to get a multimeter and see if the voltage stops with the stopping of the fan.
Run the system until the fan stops and see if the fan is still getting voltage -- if it is you have a bad fan. If it is not and the controller is getting voltage and no voltage is coming out of the controller -- you have a bad controller.
How long ago did you replace the parts? -- and why did you get a w140 control if you already upgraded?
Thanks for your input on my dilemma - the digital screen on the CCU stays on the whole time = the only time it goes blank is when you turn the ignition off and pull out the key fob.....
just to review -
i have a 99 E430 that with a built date of 10/98 - it has a newer version fan/blower motor assembly = PLASTIC FRAME - NOT metal as is shown in the pics from everybody else that's been able to splice in the W140 blower motor regulator and fix THEIR problem.......
I replaced the original blower motor with a new one - WITH the PLASTIC FRAME. Again - The blower motor assembly that I have HAS A PLASTIC FRAME - NOT a metal frame like the earlier versions on the 96-98/99's.....STILL - the problem exists
THIS is why the W140 "technique" will not work on MY E430 - the plugs are wrong, and the nomenclature of the wiring harness ON THE NEWER STYLE blower motor is INCOMPATIBLE... even WITH trying to spice in blue wires and such.... Even with the DIY directions that everyone ELSE is getting to solve THEIR problem - mine is still here like a bad relative that won't go home after a log day of visiting......
I ALSO REPLACED the original BLOWER MOTOR REGULATOR with a new Behr part - same item - The one that I have has a pot metal/aluminum type blower motor regulator - NOT the older style that works with the metal framed blower motor like everyone else...Even IF I wanted to "adapt" the W140 part in lieu of replacing with another stock or OEM part - there is NOWHERE FOR ME TO ATTACH IT TO THE BLOWER MOTOR FRAME .....STILL - the problem exists
I REPLACED the CCU, and the display now shows everything as it should be - both of my "F's" are clearly visible on the screen - everything (from what I can tell) is good as far as the CCU goes.....
SO NOW...... we STILL have the AC that has a "mind of it's own" and cuts on and off at will - if it was 75 degrees all the time - it wouldn't matter, but when its 375 degrees outside here in Phoenix with people "bursting into flames on the sidewalks" - wouldn't it be nice if the DAMN AC WOULD JUST FREAKING W O R K ?????
The only way to solve this problem is to do a little testing -- throwing parts at the problem only gets expensive.
I'm sure you understand by now that getting the controller for a older w140 S class only works if you want to do a "work around" to keep the old style blower motor. Since you had already upgraded the blower to the newer style I'm not sure why you bought this part.
I have had my motor and controller upgraded. The dealers obviously can't do the work around and they have to replace the motor when the controller goes - and from all accounts the controller is normally the first part to go.
I have never seen the parts so by looking at them I can't tell you if you have the correct parts -- I'm sure you have confirmed that you have the correct parts. Yes?
So you must get a cheap tester and see what is happening. How long have you had the new parts? Did they ever work? You could have a defective motor that is overheating and has a thermal overload that is causing it to go on and off -- same with the controller. You can get bad parts -- the dealer went to put a new instrument pac in my car -- and the one they ordered did not work?
Does all of this happen if you have it on econ and you manually try to run the fan?
Test the power to the controller and the motor - you can get a cheap tester for under $10 -- Harbor Freight has the for $3.
WAIT A MINUTE..... you wrote: "Since you had already upgraded the blower to the newer style I'm not sure why you bought this part."
I DID NOT UPGRADE - The "newer" motor assy is WHAT CAME WITH THE CAR !!! I DID NOT upgrade.... does this make sense????
ALL I DID WAS REPLACE "LIKE" WITH "LIKE" - THE SAME - "QUID PRO QUO".....
When the AC cuts off - N O T H I N G IN THE SYSTEM WORKS - NO FAN, NO EC, NO COLD COMING OUT OF THE VENTS, NO HOT COMING OUT OF THE VENTS - NO NOTHING - NADDA !!!! the only "wind" i can get is by cracking open the sun roof and lowering the windows - otherwise - no fan, no air, no heat no nothing....
I have no idea what motor/ controller would have come on a w210 with your build date. But, if your car came with the old style then someone upgraded it to the newer style at some point when one of the original component parts failed. Since this is a common failure point I would not find that unusual.
What is very confusing about the way you are writing your posts is that the fan is not the AC (air conditioner). The fan is part of the ACC (automatic climate control) - this is the heat / AC and general ventilation. When you talk about no AC -- people think that you are talking about the AC compressor operation also.
When the fan stops working -- be it the motor or the controller causing the problem -- the rest of the system is still working. You are just not getting any air blowing. All the rest of the system is still operating -- the auxiliary water pump and the duo-valve in the heater is still working when in heat mode and the A/C compressor is still working in the AC mode -- as well as all the vents.
So when you say nothing is working -- it is confusing. If just the fan stops then a lot is still working. If the whole ACC system stops working then the problem is most likely not your fan or controller - because it is not working to tell the fan to turn on.
If the whole system is shutting off you should not have bought the parts you did and if it is just the fan stopping then you need to do some testing on the wires.
It sounds like you have only the blower motor going out - to fix this problem you went out and bought both the motor and controller and after installing the new parts you have the same problem. Then you bought a new display head and this also did not fix the problem. If this is correct -- then you need to check the wires feeding the controller and see if they die when the fan stops. Like I said -- you could have received a bad part.
You may need to look at the fuses to the fan motor -- I'm not sure of any relay for only the fan -- That going over a bump would cause any changes would make me look for a bad connection. I would replace the fuse to the blower motor circuit (even if it looks fine) -- and check to make sure it does not have any other kind of safety to the blower. The blower is a high power user and it may be protected by more than one device in its power supply.
Here is the latest in my Trial of the Errant AC System
I take the car into an indie mechanic today - The charged me $50 to "look" at everything... OK... HALF of the money spent was worth it.....
The said - that the 99 year model E class CHANGED their blower fan, blower regulator and blower motor cover (mounting plate) sometime in the production year.... The Blower motor I have is one of the "updated" versions, and I need to order an updated blower motor regulator, as well as the updated blower motor cover (mounting plate)....
Hmmmmm.. now we're getting somewhere I thought - At Laaaaaast !!! some HOPE????
So I buy a SECOND blower motor regulator shown on the right below is the Updated version next to the first one that I ordered to replce the one that came with the car - also the same style
I already have the updated cover - so I rush home after telling my wife that HER car will NOW HAVE AC ONCE AGAIN - looking forward to being the best-est hubbie in the whole wide world!!!
I get the parts installed - and now - the fan works great, but there is NO COLD AIR !!!!!
W T F ?????
So now I DO have "wind" coming out of the vents on a regular basis, but the ice cold air that USED to come out (off and on with no rhyme or reason as to cutting off, etc.) now comes out hot, even when the thermostat is set to 72 or below......
I ran a diagnostic AGAIN.... - the ONLY error code I got was b1232 - Refrigerant pressure sensor (B12)