How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Marty Your Own Question
Marty
Marty, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 53904
Experience:  Bosch Certified Master Technician with over 35 years experience in the automotive industry.
13230946
Type Your Mercedes Question Here...
Marty is online now

When starting from cold and sometimes after car has stopped

Resolved Question:

When starting from cold and sometimes after car has stopped for a short time, internal heater fan comes on full power on hot, it cannot be switched off by any controls and can stay on for upto 10/15 minutes then it will go off on its own. This is causing problems now the weather is getting warmer.
Car is E280, 2001 model tiptronic. with 109000 miles.
Can you help??.
Submitted: 3 years ago.
Category: Mercedes
Expert:  Marty replied 3 years ago.
Hi, my name isXXXXX this problem occur when the key is off?
Customer: replied 3 years ago.

No, problem only starts when engine is started. Approx. 30 seconds after engine is started fan comes on full power and will stay on sometimes for upto 10/15 minutes getting hotter as the engine warms up. On occasions fan will come on whilst car is being driven after travelling several miles and blows hot air into the car. Again it will stay on for several minutes before switching off again. An intermittent fault somewhere.

Expert:  Marty replied 3 years ago.
Ok, will this happen if you are using the air conditioning? In other words will the problem suddenly override the current setting of the climate control?
Customer: replied 3 years ago.

Hi Marty,


The car has air con not climate control. As I said in my original mail, you can not stop the fan by pressing any control or even switching the air con off.


Switching the fan control to off or adjusting the temp controls makes no difference. Even with the temp controls set at cold the fan blows hot air at full power into the car when it decides to come on !!.


Hope this info helps and that you can put forward a solution.

Customer: replied 3 years ago.

Is this a problem you cannot solve ???.

Expert:  Marty replied 3 years ago.
Hi Tony, sorry for not replying yesterday I never saw your reply in my inbox.

Can you post the vehicles 17 digit chassis number for me.
Customer: replied 3 years ago.

Hi Marty,


Chassis No of my car.


WDB2100632B086188



Trust this helps.


Tony.

Expert:  Marty replied 3 years ago.
Hi Tony, there are two possibilities for this symptom. Either the a/c control in the dash is intermittently shorting or the electronic blower regulator at the blower motor is shorting. To test for this problem the white/pink wire to the blower regulator needs to be disconnected while the problem is occurring. If the blower turns off then the problem is in the a/c control in the dash. If the blower continues to run with the white/pink wire disconnected then the blower regulator is the problem.

Let me know if you have any questions.

Marty

Please be sure to rate my service!
Marty and other Mercedes Specialists are ready to help you
Customer: replied 3 years ago.

Hi Marty,


 


Thanks for info, will have this checked out and if necessary come back.


 


Thanks,Tony

Expert:  Marty replied 3 years ago.
You're quite welcome Tony.

Please don't forget to rate my service!
Customer: replied 3 years ago.

You were right, it was the fault of the resistor on the heater fan.


Replaced, now OK.


Thank you,


Tony

Expert:  Marty replied 3 years ago.
I'm glad everything worked out Tony.

Related Mercedes Questions