I have a base model '05 Roadster and I was wondering what the interior lights consist of in the base models. The only lights that I have are two lights at the top of the windshield header. I can either turn them on or off manually. They do NOT come on when the doors are opened. Is this normal? I figure if it was a fuse problem they would never come on. Any help or suggestions would be greatly appreciated.

 

First question : If you leave the key in the ignition and open the driver's door, do you get a beep ?
As you can see, it is a bit complicated :
The door switches tell the Central Locking Pump if they are open or closed.
It then sends a tweet to the Body Control Module.
The BCM then supplies a ground to the dome light, then after a period of time it gradually removes the ground so the light seems to just fade out. ( If the dome switch is in the "auto" position. )

 

There are two switches - one turns the lights on/off, the other turns the "auto" feature on & off. Is the auto switch set wrong?

 

Yes, if I open the door with the key in the ignition I get a beep. I can turn the lights on if I hit the switch highlighted with the yellow dot. I can also turn them on if I slide the bar over to the "O" highlighted by the blue dot. Regardless of which position the lights are on when I close the door they stay on, they never fade out.

 

SUBSCRIBED .. thinking we have the same issue with our roadster.

 

Use an ohm meter and measure the voltage on pin 3 of the dome light connector with the switch in auto with the doors closed.
You should see 0 volts when you open a door.
Also at this time, measure pin 3 to ground, you should see close to 0 ohms.

 

You have the right idea, the Service Manual has a routine that checks the circuit and supposedly tells you what is wrong. In this case the worst case is replacement of the BCM they say.

No wonder techs are swap happy, start with the expensive part and work down through the list. I can't see why they did not start the parts replacement at the CLP/SSM.

If nothing works, they shrug their shoulders and go for lunch. Not their problem, they take their share of the money for all those parts and get ready for the next sucker.

 

Having looked here and there at this issue.. Not really diving into it.. "could" the BCM be the issue with no other malfunctions other than the interior lighting.. I say that knowing the answer.. LOL.. lets say probability of it being the problem..

 

Riddle me this.. switch in the "automatic mode" for the dome lights.. lights stay on. They never time out.. as in normally when door is left open after a while they still time out - or when car is started. Put the roadsters (problem car) BCM in my coupe.. works fine. So are we off to check the Security pump module time? If a door switch is bad .. would it prevent the module from eventually timing out?

Lighted door sills await your resolution..

 

I had the same problem and it my assumption the feed for the fade out feature is done buy the earth in the tailgate micro switch, which is fitted into the internal of the tailgate latch. Mine had no earth return from the common terminal of the micro switch to earth, I fitted an earth from this terminal and now it works perfectly. saltiga

 

I think if a door switch is 'bad' meaning it never gets to the door closed position then the lights should time out just as they do if you leave a door open.

 

With the switch in auto, the light should fade out when the door is closed or locked (refer page 60 of owners manual) Page 61-- battery saver feature, if the door is left open the interior light turns off automatically after 15 minutes. I do not know what would happen if the door switch malfunctioned but I do know my tailgate switch was faulty and with all doors and the tailgate closed the fade out did not function, but the 15 minute time out did. I would suspect the time out feature would function if the door switch was faulty. Satiga