Odometer and radio on; key out of ignition

[Ron and a 1996 BMW Z3]

I have an issue draining my battery overnight. With the key out of the ignition I still have the odometer, radio and clock on. I replaced the ignition switch but it didn't solve the problem. Internet said that was most likely the problem. Next I will replace the ignition lock cylinder. Does anyone have experience with this problem? My car is a 1996 BMW Z3 1.9 liter

 

[colb]

Don't think it will be the lock cylinder, sounds like a fault in one of the modules or Instrument pod maybe a short allowing power to feed the items. You ruled out the electrical part of the ignition lock by changing the switch.

 

[Stevo7682]

Since you have 2 things on first question is it an original or aftermarket radio if aftermarket check wiring.
If no joy next thing is go to fuse box pull the fuses one by one see which one kills it then trace fault from there.
Stephen.

 

[Ron and a 1996 BMW Z3]

Don't think it will be the lock cylinder, sounds like a fault in one of the modules or Instrument pod maybe a short allowing power to feed the items. You ruled out the electrical part of the ignition lock by changing the switch.

Thank you for your reply. I have yet to figure it out and it's been months. I may have to take it to someone someday but fear the costs to fix it. I am thinking it could be a ground somewhere, a brake light switch at the pedal? For awhile the lights on the dash would stay on then when I pressed on the brake they went off. Now it's not doing that. Screwy stuff. I will keep on keeping on when I can find the time and motivation.

 

[Jen]

Hi, just wondering if you have solved your problem yet? I have a Z3 2.0 with the same problem, odometer stays on when key taken out of ignition, press brake pedal and odometer goes out.
We took each fuse out and found when fuse 46 was taken out, the odometer went out.
if You have resolved the problem, I’d love to know. Many thanks
Jen

 

[NZ00Z3]

It is likely a problem with the instrument cluster.

See the relationship with it to the brake switch and clock (board computer).

The instrument cluster has several power supplies to it, some are hot all the time, so a weak back track in the cluster could power items supplied by F46 until there is a load applied to the back track via the brake switch.

 

[Jen]

Thank you for that, we’ll investigate the cluster.

 

[Jen]

As we had changed the battery over a few times (because of being flat). I decided to take it for a 20 mile drive twice, on dual carriageways, leaving it for an hour between. The odometer has now gone out and it started first time this morning when I needed to move it off the drive. Fingers crossed that it’s ok now, and that it was something to do with the battery learning.