1997 BMW 740 heater /AC fan keeps runing never stops when e

Tiny
BMW7401
  • MEMBER
  • 1997 BMW 740
  • V8
  • 2WD
  • AUTOMATIC
  • 194,000 MILES
Hi 2 carpros
just happened suddenly the fan in my bmw 740i 1997 keeps runing after engine is off and can hear it runing under the dash board(faint but can be heard) noticed my battery is dead each next day a mechanique I trust told me it could take up to 8 hrs to figure out all the circuits to pin point the source, currantly after I recharged the battery I unplug either trminal to stop it from bieng drained, is there a fast way to know wich computer relay or circuit to pin down. Is that normal?
please help
its my first time to try this site dont know what to expect
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Thursday, February 11th, 2010 AT 8:13 PM

10 Replies

Tiny
DR LOOT
  • EXPERT
I had the same problem with my 1997 740IL it is not the heater fan that you hear, what you hear running is the climate control fan, stick your head down by the shifter as close to the climate control unit as possible and you will hear the noise, I had to replace my climate control unit, you can probably find a used one at your local European junkyard, but for now you will have to remove the climate controlled unit and unplugged the little roller fan, so your battery does not continue to go dead until you find another climate control unit.

Due to the high volume of no responses to posted questions, if you have not resolved your issue and you need further assistance, please respond.
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Thursday, February 11th, 2010 AT 8:49 PM
Tiny
DR LOOT
  • EXPERT
Thank! If you have any more issues feel free to let me know.
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Friday, February 12th, 2010 AT 7:34 PM
Tiny
BMW7401
  • MEMBER
Hi dr. Loot
why do I smell coolant inside the car after the heater runs for a while while driving
thanks
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Sunday, February 14th, 2010 AT 9:38 AM
Tiny
DR LOOT
  • EXPERT
If they heater core is leaking, it has a drip pan with two drain ports on the right and the left side of the rear of the transmission you will see coolant on the ground about the middle of the car, if for some reason it is leaking out of a Hose, the Carpet inside the vehicle may be wet, on the side of the console toward the firewall, why don't you check it. You may also have a coolant leak in the engine compartment, how much coolant is it using? Check to heater hose connection at the firewall on the left side behind the engine make sure it is not leaking their. It takes a special adapter to pressure test that BMW you may have to take it to a shop and have them pressure test to see where you're coolant leaking. Let me know what the results are.
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Sunday, February 14th, 2010 AT 11:18 AM
Tiny
BMW7401
  • MEMBER
Hi dr. Loot
thank u again I did put new coolant hoses 2 wks ago after one hose busted and coolant was all over my driveway, I checked my carpet as u requested very dry I put paper under car to check for amount of leak it was in the front about I would say a 1/2 a tea spoon in one day may be less, but still do u think the smell could be coolant remnants of the hose leak?
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Monday, February 15th, 2010 AT 7:42 AM
Tiny
DR LOOT
  • EXPERT
I believe that if you "busted" a coolant hoes that most likely there is coolant residue all over the engine and that is probably what you are smelling. Also the coolant leak that you have stated, you could also be smelling, tell me exactly where the "leak it was in the front about I would say a 1/2 a tea spoon in one day may be less" is located.
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Monday, February 15th, 2010 AT 6:20 PM
Tiny
BMW7401
  • MEMBER
Hi again dr. Loot
i would say the leak is about 16" to 20" from the front of the car
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Tuesday, February 16th, 2010 AT 3:32 PM
Tiny
DR LOOT
  • EXPERT
If it is directly in the middle of the car 16 to 20 inches from the front bumper it is probably the water pump. I hope not you will have fun with that job!
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Tuesday, February 16th, 2010 AT 9:10 PM
Tiny
BMW7401
  • MEMBER
Well dr. Loot that what I think it is thank u for the help am not a mechanic but at least I know what it is
u r a STAR.
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Wednesday, February 17th, 2010 AT 3:28 PM
Tiny
2CARPROS LINSEY
  • MEMBER
We appreciate your donation and look forward to helping you in the future. Thank you
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Monday, March 1st, 2010 AT 4:33 PM

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