# 01 740iL - Trouble with nav system



## faheem1 (Oct 28, 2008)

Nav goes gray much with random inteference pattern lines much like a TV that is receiving no signal. However audio system (Radio and CD player) continue to work but every 2 minutes and 40 seconds the sound goes completely dead. I need to push the on/off button once to turn power off, and a second time to turn power on. Upon turning on audio system comes backto normal. Screen stays scrambled.

I have tried disconnecting and then reconnecting the NAV unit, which worked a few times, but that is no longer working. I even tried disconnecting the battery and then reconnecting. The problem still persists. I find it hard to believe that the NAV unit is broken because a lot times the indicator "on" light is lit up orange. I tend to think it is some sort of wired connection issue.

Is there any recall or campaign on the 2001 740il NAV units? Please advise.


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## M.Wong (Jan 9, 2003)

That might be an ignition switch issue, take a look at this: ignition switch issues.

Here was what someone told me to do - with the car running and the radio on, try flipping down the passenger visor then slide the mirror cover open so the light comes on. If the radio and/or screen goes out (I know it sounds crazy) the ignition switch is likely the problem.

If you don't have any luck here, you might try these two places:

NAV forum.

NAV reference (Second section down, right column)


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## sealbeach740 (Sep 5, 2003)

I see you have a 2001 - does it have the 4x3 (square) or 16x9 (rectangle) screen? If it isn't the ignition switch, and you have a 16x9, it's very likely you have a MKIII Nav unit. That said, the MKIII's are vunerable to the power being disconnected before the red LED goes out. Your symptom of the radio going dead, then back on if you turn it off then back on again, describes the issues seen with a dying/dead MKIII.

The most easy way to test is to borrow someone else's MKIII & see if your problems go away. Be sure to wait for the red LED of the Nav unit to go off before pulling the power to the Nav.


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## M.Wong (Jan 9, 2003)

sealbeach740 said:


> That said, the MKIII's are vunerable to the power being disconnected before the red LED goes out... Be sure to wait for the red LED of the Nav unit to go off before pulling the power to the Nav.


*I forgot about that warning, good reminder! *

TIS text from BimmerNav.com:


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