cthang

Hi,

I am having problems wiht my 2007 A4 3.2L. The car runs fine during the day once I park it over night the battery is fully drain in the morning. I boost it up and it runs fine all day until the morning again. I brought it the dealer and they found that the stereo/navagation is draing the battery overnight. So I replace the stereo/navagation and the problem is still there.

Anyone run into this type of problem or know how to diagnose a battery leak?

Thanks

adamstasiak

How is your AC fluid?
Sometimes when you do not have enough pressure there the system will try to equalize and it will be pumping it all night.

Go to some parkade with heat and after 1 hour test your AC either it is working. I had this problem on the A6, added the AC fluid and it stopped.

Also check your trunk lights.

ok2000A8

I'd also check for vacuum leaks; especially on door lock system. Vacuum pump may be running a long time. Also check vacuum pump. I've also had faulty fuel pumps and an old nav system that wouldn't shut off after car was shut off, so drained battery.

cthang

thanks,

I will take that into consideration. On another note if I disconnect the stereo/nav system the car starts fine over night.

voodooca

Have you had someone test the battery?
Not just if it starts or not...
Cause there are little things that drain a battery while your car is sitting, but if the battery is not capable any more, then it will go dead with very little draw on it.

Chad

cthang

yeah I replaced the battery and the next day it was dead.

ok2000A8

You may wish to review Nav system wiring. If it's a new aftermarket system, be sure that the power line is ignition activated and not a constant "on". This will drain battery even when car is off. Previously, when I had similar situation, I had a l
"Drain test" done on car. Anyone with a vag com, etcn should be able to tell you how much power is being drawn by car when car is off. You should be able to get a print out of result. In my case it turned out to be multiple successive faulty Crappy Tire batteries. I required 3 warranty replacements within first year. If you say all is fine with nav system disconnected, it'd be very interesting to see what system draw is with car off and with nav system connected and then with it disconnected. Depending on what you find, it should lead you to a next logical step.

cthang

Figured it out. It is my telephone module that is draining the battery.

Thank you all for your input.

ynd900

Hi chtang,

Do you have a little more details about the telephone module, if it is the one in the armrest and how you disconnected it? Because I have the exact same problem, I took to the dealership and they also told to change the navigation system, however it is working perfectly. It seemed to strange to me, therefore I completely disconnected the nav system and still had the drain problem.

Another question did your bluetooth system stopped working when you had this drain problem?

Thanks for your help.

cthang

Hi ynd900,

The dealer thought it was the nav system so they replaced it on warranty and it still drained the battery the next day. To disconnect the phone remove the fuse labelled 'telephone' that stopped my battery from being drained. Yes my bluetooth stopped working as well, that is the telephone module. If it is on warranty Audi would replace it. They didn't fix my phone module becuase they blamed it on my command start for killing the module.