I have a battery drain problem.Dealership and 3 mechanics can't find the source. on 2003 BMW X5

Current draw tests done twice by Dealer and BMW specialist & no problem found.If we don't plug in a charger it will drain within 1 to 3 days. Battery replaced several times. Main battery cable replaced. Secondary coolant pump replaced. Alternator replaced twice. Driver seat relay replaced. This has now been going on for over 2 years. Dashboard odometer lost pixels, cant read it or the outside temp display. Don't know if it can be related. Also get inaccurate warnings from dashboard like check engine oil, brake linings coolant level, etc. Thanks for your help.

by in Marietta, GA on October 17, 2012
2 answers 2 comments
ANSWER by on November 03, 2012
Does your vehicle have factory navigation? I've seen mysterious battery drainage problems that lead back to the navigation module in the luggage compartment. You can unplug it and see how it affects your battery issues. Good luck.
COMMENT by on November 05, 2012
Thanks for your response. It doesn't have factory navigation.
ANSWER by on June 06, 2014
I had a similar problem and it was due to a faulty temperature regulator that sits behind the lower dash and is accessible from the passenger's footwell. This regulator controls some sort of fan which would continue to run an hour after turning off the engine thereby sucking the power out of the battery. Simple replacement by my mechanic that solved the problem. Apparently common issue in 2003 X5's due to bad sensor.
COMMENT by on June 08, 2014
The end stage resistor had been replaced some time ago. It's possible the problem started after it was replaced. It's been too long to remember. It would be likely it would have been found to be the problem after all the testing, but who knows. We still plug it in every night. Thanks for the input.