BimmerFest BMW Forum banner

Electrical Confusion

5649 1
Hi. I drive an Irish 2002 520i Facelift. Right hand drive. Construstion year November 2001.

I'm having some frustrating electrical troubles.
To begin with, the electric window/electric mirror switch on the the driver's door doesn't work. The speaker does work and the car knows when the door is open. I know the window regulator works as I can open and close all the windows with the key. The window switches on the other doors do work. Including the boot release button.
The front passenger door speaker doesn't work.

Theres a problem with the lights. The rear driver's side cluster (one with all the fuses behind) doesn't work at all. The car is telling me there is a problem on the instrument cluster. The rear passenger side works fine. The rear middle brake light also works.
When I turn on the side lights, the front passenger side angel eyes light up without issue (No light problem with that unit at all). The front drivers indicator lights up steady. No angel eyes light. When I turn on the dip beam, one of the angel eyes light as does the dip beam. The indicator turns off. Full beam works but still just the one angel eye lights. When I turn on the front fog lights the passenger side doesn't light. The instrument cluster only tells me there is a problem with the rear light cluster. The front hasn't recorded a problem.

The airbag light is also on.

I checked all the fuses and nothing is blown.

I got sick of this problem so I brought the car to a mechanic with the X431 Diagnostic system.

The diagnostics reported 11 faults with the light system. Even with the lights that do work.

The airbag system recorded 2 faults: Faulty seat occupency detector and belt tensioner, front passenger.

2 other faults: Outside-temperature sensor. Gong tone (T3).

7 faults with the engine system: Activation, map cooling. Fuel trim bank 1 & 2, permisssible range exceeded. Bank 1 & 2 control limit. Control units, self-test. Activation, fuel-pump relay.

5 faults with locking system: Central-locking drive, passenger's door. Central-locking drive, driver's door. LED for anti-theft alarm system, open circuit. Fuse or lead for load circuit 1. Passenger-compartment sensor.

I only have trouble with the lights and airbag light.

The mechanic reset all the systems baecause he said it might solve some of the issues. All it did was turn off the airbag light when no-one is sitting on the passenger seat.

If anyone could help or have any advice I'd appreciate it. Is there 1 main system that could be causing all the other faults or is ther dodgy wiring somewhere?

1 - 2 of 2 Posts
I have an infrequent problem with the passenger seat: Twice, I've had the code for the "seat occupied" detection. There is a small box under the seat, towards the rear, with two connectors on it. I fiddled with the connectors, reset the light, and the problem went away. I used the Peake SRS tool to diagnose/reset.

Outside temp: does it read -40 deg? Replace the sensor.

Is this guy a BMW specialist? If not, find one with a DIS. Many of these problems could be traced to the GMIII - the general module, which directly, or indirectly, controls much of the ancillary equipment. A good tech s/b able to run these down.

BTW, have you had the battery load-tested, and the alt output verified? The electronics are quite sensitive to battery voltage.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.