electrical problem w202 aircon fan running all the time

[lars-mad]

Hello i got this problem with my c200 w202 when the car is running the aircon fans in the front of the car is running all the time also the engine temperature is not showing on the gauge this started rescently after the car has been inside a garage for 2-3weeks

does anyone know where to start looking for the problem?



Cheers
Lars

 

[carat 3.6]

Sounds like your engine temp sensor is not connected or faulty. The air con fans are running because the ecu dosent know how hot the engine is, so runs the fans to prevent engine overheating.

 

[lars-mad]

Sounds like your engine temp sensor is not connected or faulty. The air con fans are running because the ecu dosent know how hot the engine is, so runs the fans to prevent engine overheating.

Where are the temperature sensor located?

 

[BlackC55]

Before you do anything get it on a Star. This will save you time and money.

 

[lars-mad]

Before you do anything get it on a Star. This will save you time and money.

Allready done that have star diagnosis right here... it says that the sensor is faulty changed it and still the same...

 

[TonCoronel]

Hmmm thats strange, maybe it has to be coded(Dont think so) or there is a teach-in process via the star-diagnosis needed.
Or do you mean that after you replaced the sensor it still showed up as faulty on the star-diagnosis

 

[lars-mad]

Hmmm thats strange, maybe it has to be coded(Dont think so) or there is a teach-in process via the star-diagnosis needed.
Or do you mean that after you replaced the sensor it still showed up as faulty on the star-diagnosis

it was before i changed it will go out now and check what the computer says

 

[BlackC55]

You need to check the wiring and the connections to the fan control module.

 

[lars-mad]

the fault is coming up and when i erase it the fans are shutting off for some seconds and then it starts again and the fault are coming back B1472 coolant temperature sensor B11/4
the funny thing is that the fuel sensor started working after erasing the fault codes but the other fault is coming back

 

[TonCoronel]

If the fault is coming back then the sensor isnt the problem, must be the wiring then. I dont think this sensor has his own fuse?

 

[brucemillar]

I had a fan control module fail in my W203 C240. That caused all sorts of whacky errors and erratic fan behavior. FYI. STAR called that out as a temp senor fault. Replaced both temp sensor and coolant level sensor with no change in fault. replaced fan control module (well the whole assembly from a breaker) problem solved.

 

[BlackC55]

A star won't pick up if that control unit is faulty.

 

[lars-mad]

exactly where is the fan control module located and what does it look like? i think i have a spare at a donorcar i got...

 

[brucemillar]

In the w203 it is in the fan housing at the bottom of the unit. It has a dust cover over it. When I opened mine up it had collected a load of water. I hope that this helps.

 

[A17 LTF]

On the W202, the fan control module is located under the passenger side front wheel arch. You have to take the front lower plastic inner cover off which should be secured with 3 10mm nuts. The module is then secured with 2 10mm nuts, although there is a good chance it may take some wd40 and a bit of effort taking them of. Type it into ebay and that will give you an idea of what it looks like.

 

[lars-mad]

changed the fan control module and temperature sensor but still no luck will read out the codes from star

 

[mersum1es]

Check all fuses (boxes both sides in engine bay, K40 relay module), battery voltage and groundings. This is very common when ECU is not having proper voltage.

 

[lars-mad]

Check all fuses (boxes both sides in engine bay, K40 relay module), battery voltage and groundings. This is very common when ECU is not having proper voltage.

This is a pre facelift car so it has just fuse box on one side of the engine bay as far as i know but will continue the investigation.. have star diagnosis so i can take a picture of the fault codes just in case

 

[Grey Area]

lars-mad I'm having the same problem, did you ever get this resolved?

p.s sorry for starting a new thread about this everyone -search fail-

 

[lars-mad]

lars-mad I'm having the same problem, did you ever get this resolved?

p.s sorry for starting a new thread about this everyone -search fail-

problem is still the same after all this years ended up put in an new gauge on the a pillar so i at least can monitor the engine temp

if anyone has a fix let me know