Dome Light Not Working-Need Diagnostic Help
 

Edit: SOLVED: My issue was the GM3. Replaced it with one I got at a junkyard of the same year (2003). The interior lights now work properly again.

I need help diagnosing my issue and following this wiring diagram. What am I looking for and where to test?

Problem: Front overhead dome light does not work. No interior courtesy lights work. I was able to short (not sure which wires now) inside the dome light and all the interior lights and dome light illuminated. Figured I had a bad switch. Replace the dome light fixture and still have the problem.

Not Working: Front Dome Light, all courtesy lights.

Works: Front map reading lights, front amber led ambiance lights, rear dome lights, rear map lights.

Door contacts: I "assume" the door contacts work because (1) if a door is open, the central locking does not lock the doors but does when all doors are closed, (2) if I open a door while driving the dash displays "door open."

Attachment 81958

Where does X10148 go? A short could cut the circuit. I'm in the same boat. All of my interior lights don't work. My X5 is out of state for suspension work. However, I suspect mine has a relay problem. It's one located above/behind the glove box fuses. I've ignored it for a while. I'll have to fix it sometime.

Looks like a connector behind the glovebox. I guess testing continuity between X10148 (which pin?) and the dome light connector pin 8 may be a start. Connector X10148 also goes to all the entrance/courtesy lights. I was able to illuminate all those courtesy lights by shorting one of the wires in the dome light (need to figure out which one). But that would imply I have continuity anyways from the dome light, through connector X10148 to the entrance lights.

Attachment 81959

If the dome light is not working but poking voltage there light up the courtesy lights the wiring from connector X10148 is working like it should and there is no voltage from GM3 to that line powering dome and courtesy lights.

Can you explain further what you mean by GM3 and where that is on the diagram?

If I jump power from Pin 1 (always hot) to Pin 8, all the courtesy lights illuminate. If I jump Pin 1 to Pin 7, nothing happens. Does that mean I want to focus on tracking back from Pin 7?

GM3 is the general module which should give the supply voltage for this lighting. From pin 8 you can bypass the voltage backways to other lights via connecting point X10148. Pin 7 is the switch.

Cool. So the connector posted is a GMIII connection. I'll have to try that trick when I get access to my X5 again. More and more I'm thinking I may need a new GMIII module. It was repaired once. If it was not for coding, I would have another already installed. Since F60 is giving me trouble, that circuit also needs testing too.

Can someone clarify my understanding of Pin 7 & 8 at the interior/reading lamp.

Pin 7: This is closing ground right? When I press the dome light switch, I should be able to measure continuity at pin 7 and a grounding point on the vehicle right?

Pin 8: What triggers the + power to pin 8? My "guess" is either when a door is opened or pin 7 ground is closed.

I am trying to understand this circuit to further troubleshoot my issue.

Both assumptions appear sound... but have you read the owner's manual on this switch?

https://i.ibb.co/NtfHfwX/Lamps.jpg

Any chance you have held the button down for 3 seconds and shut them all off? ;)

Pin 7 is a triggering grounding switch. When you press the button pin 7 is grounded as long as you press the button. With shorter presses on/off and longer over 3 s press disables the interior light until it's switched on again.

Quote from WDS:

Interior lighting and load cut-out

The interior lighting is controlled by following switches and systems:
• Button at front of central light unit
• Door contacts
• Terminal R and terminal 58 (parking light)
• Central locking
• Remote control lock system
• Airbag control unit

Button

The lights of the interior lighting system can be switched on and off by means of the button at the front of the central light unit. However, the lighting is still controlled automatically by the general module.
This means the interior lighting switched off by means of this button would be switched on again by opening a door.
As a special function, the interior lighting can be switched off permanently when the button is depressed for longer than 3 seconds. The system reverts to automatic mode when the button is pressed once again.

Switch-on conditions

• Button pressed
• Vehicle door open
• Terminal R switched off when the parking light (terminal 58) was switched on within the past 32 seconds
• Registering bump or impact by airbag control unit.

Switch-off conditions

• Button pressed
• Immediately after closing a door and switching on terminal R
• Immediately when all doors are closed and the vehicle is locked.
• After 20 seconds when a door is closed and terminal R is OFF.
• After 16 minutes when a door is held permanently open.
• After 20 seconds when the lighting is switched on by switching off terminal R.
• After 8 seconds when the lighting is switched on by remote control.

Load cutout

The following lights in the vehicle can be switched on when the vehicle is parked:
• Reading light
• Glovebox lighting
• Engine compartment and luggage compartment lighting
The voltage (B+ supply) for these loads is supplied by the general module.
To ensure the vehicle battery is not discharged when the lights are switched on permanently, the general module switches off the B+ supply 16 minutes after switching off terminal R.
These loads are switched on again when terminal R or 15 is switched on in conjunction with a signal change at an input of the general module or peripheral module, e.g. opening a door, opening the front (bonnet) lid, unlocking a door.