Aspheric motor running continuous

[Drivingapos]

My 2001 C240 has the aspheric motor, located in the rear view unit, this motor is running continuous. Because of this, the battery is being drained when the vehicle sits for 1 day. I found out on this site what the little motor was called in the vented area of the control unit. Now, I jst need some pointers as to why this motor keeps running. I found this out by sitting in the car after the ignition was switched off and the motor did not quit pumping. Is it a sensor? relay? if so where is the relay? Any help would be greatly appreciated.

 

[television]

Not sure which motor-pump you mean any more details.

Malcolm

 

[Blobcat]

It's the little fan behind the grill up by the rear view mirror.

 

[jberks]

It's the little fan behind the grill up by the rear view mirror.

I agree with Blobcat - sounds like the ambient temp sensor fan, though why it should still run when the ignition is off I don't know.

 

[Blobcat]

Here is another thread with a few details; http://forums.mercedesclub.org.uk/showthread.php?t=23635

 

[television]

I will have a look later in the day, cant guarantee anything.

malcolm

 

[Drivingapos]

I agree with Blobcat - sounds like the ambient temp sensor fan, though why it should still run when the ignition is off I don't know.

Yes=it is the ambient temp sensor. I am waiting to find out if anyone has had this problem before I take the control unit apart and unplug the thing. Do you thing that it will hurt anything?

 

[Drivingapos]

I called my local Benz dealer in Knoxville, Tn and as usual they were not very helpful.

 

[Drivingapos]

I will have a look later in the day, cant guarantee anything.

malcolm

Iwill keep checking this forum through out the day, but I really appreciate you guys trying to help me. I really love this little car but it has almost convinced me to sell it, before something really big happens to it. I should have done my homework before I bought this car but I just assumed (we all know what happens when you do) that they were fine vehicles but was I wrong. Beautifual but def. not fine. Thanks

 

[jberks]

Yes=it is the ambient temp sensor. I am waiting to find out if anyone has had this problem before I take the control unit apart and unplug the thing. Do you thing that it will hurt anything?

Sadly, unplugging it will send the heater haywire. Interior temp control will be a problem.
I can't understand why it's live with the ignition off though. Possibly a fault on the climate control unit? I've certainly not heard of the fan staying on before, though there are lots of fans and bits that stay on for a while after shut down. Are you absolutley certain it's the fan?

 

[television]

Sadly, unplugging it will send the heater haywire. Interior temp control will be a problem.
I can't understand why it's live with the ignition off though. Possibly a fault on the climate control unit? I've certainly not heard of the fan staying on before, though there are lots of fans and bits that stay on for a while after shut down. Are you absolutley certain it's the fan?

I too having been thinking about this, I always thought that this all got killed with the key, the only thing live is the REST unless a smiconductor has broken down in the control unit or is this on a thermo device. JB do you know if this thing runs on for a time when the car has stopped.

Malcolm

 

[Uncle Benz]

This fan running is an indication that your CAN BUS is staying awake. The most common cause is the seat control unit.( there is one under each front seat ). Try unplugging the units and seeing if the battery drain disappears. There are other faults that can cause CAN BUS to stay awake after shutdown, but seat controllers are the first place to look. Diagnosis can be difficult even with a Star machine. Good luck!!

 

[Drivingapos]

Sadly, unplugging it will send the heater haywire. Interior temp control will be a problem.
I can't understand why it's live with the ignition off though. Possibly a fault on the climate control unit? I've certainly not heard of the fan staying on before, though there are lots of fans and bits that stay on for a while after shut down. Are you absolutley certain it's the fan?

yes. I sat in the vehicle and even had my wife do the same thing and we both came up with the same observation. A friend of mine suggested that a relay maybe defective and is sticking. Ever heard of that?

 

[Drivingapos]

This fan running is an indication that your CAN BUS is staying awake. The most common cause is the seat control unit.( there is one under each front seat ). Try unplugging the units and seeing if the battery drain disappears. There are other faults that can cause CAN BUS to stay awake after shutdown, but seat controllers are the first place to look. Diagnosis can be difficult even with a Star machine. Good luck!!

can you please explain what these can bus controllers are for. Just the seat controls or is one a phone interface. Are these things expensive to replace or should I just take this car to the shop? I really like the new Nissan Altimas

 

[television]

A Can bus is a dual data check system that checks averything effected by the driving of the car. On your car being a 99 it is is only used in a very limited way. Full OBD2 did not start till around 2000-1, I am not sure if the CAN was used to put the car to sleep back then, and have only seen it on 2001 cars. Its all room for thought though.

Malcolm

 

[type49]

A Can bus is a dual data check system that checks averything effected by the driving of the car. On your car being a 99 it is is only used in a very limited way. Full OBD2 did not start till around 2000-1, I am not sure if the CAN was used to put the car to sleep back then, and have only seen it on 2001 cars. Its all room for thought though.

Malcolm

Malc, his is a 2001! Though this could be a 202 or 203 so we're none the wiser. Can't think of anything except CAN lines or heater control panel itself, which could cause this fault but without knowing chassis number & looking on a wiring diagram to confirm feeds etc, all we can do is guess.

 

[jberks]

yes. I sat in the vehicle and even had my wife do the same thing and we both came up with the same observation. A friend of mine suggested that a relay maybe defective and is sticking. Ever heard of that?

I don't think so. I doubt its' relay controlled as its pretty low current. The can bus suggestion sounds the strongest candidate at the moment, though exactly what this does is a bit of a mystery to me, but they are known for not going to sleep and for dragging down batteries and if they have gone down, they control all sorts of things so the fan could be a symptom.

 

[Drivingapos]

My car is a 203 chasis andwhen I unplug the control units under seats, do I leave them unplugged or do I just unplug them and plug them in before I get out of the car for the day? Thanks

 

[Drivingapos]

I forgot to tell you guys that the only thing I get on my lcd is SOS, visit workstation. It does not stay as a fault but goes out shrotly after the ignition is on.

 

[Drivingapos]

Does this car have an OBDII plug station? If so will it read the codes? even if it does not stay as a malfunction on the computer