05 330ci Conv....Car runs great and then all of a sudden Horn stops working, heated seats don't work and all switches on console just above ash tray stop working, brake lights are now on all the time and the Conv top switch is dead. and the a day or so everything works again. But another day or so and they are off again. H E L P
How old is the battery? Google “BMW E46 hidden obc functions.” One of the tests shows the voltage as seen by the engine computer (DME in BMWspeak). Check and report back the voltage when the:
- ignition is in the accessory position
- ignition switch is in the run position with the engine off
- engine is idling
- engine is revving at 2000rpm.
Also, try a reset:
- disconnect the negative cable from the battery
- disconnect the positive cable from the battery
- short the cables together for at least 10 minutes
- reconnect the positive cable to the battery
- reconnect the negative cable to the battery (sparks are ok)
- reset the clock.
It could be a CAN issue. I once had an intermittent dead gauge cluster, no turn signals, and other oddities that would randomly come and go. Finally solved it by taping broken and crossing wires in the plug for the rear view mirror.
In addition to the above recommendation for battery and reset, look through every connection in the car for broken/damaged plugs, wire shorting, or anywhere that water could be intruding into wiring.
First off check the voltage at the battery with the car off, then start the engine and test the voltage at the positive and negative terminals near the drug bin under the hood.
Battery should be 12.6 with engine off, and the alternator should be 14 or higher.
Insufficient voltage will cause the modules to behave badly.
It may be a bus issue, but I'd check power first.
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