Electrical problem? inside light not turning on often.

Dear all,
I have 1999-323i 4 door Sedan. I've had this experience for a long time, but didn't really bother to ask mechanics because I know they wouldn't know for sure either and will just charge huge $$$ just
diagnose it. But recently found this great Usenet group, and hoping that I could get some answers.
This light above front seats -- in the middle, that you push the switch located on the roof to turn it on, or it turns on when the car door opens with the lights in the back seat area. The back seat lights turns on ok, but this little light above doesn't turn on most of the times. I know it's not blown fuse or the light bulb itself, because it does come on occasionally.
It is very odd that if I push the switch to turn it on while the key is in ignition, the back seat lights come on (but not the front light above), but they wouldn't turn off if I push the button again. It works sometimes, and I don't see any pattern when it works or doesn't.
I had this issue for a long time, maybe after 3-4 years after the purchase, but didn't bother to look into it because it's not that serious issue, but annoying.
Does anyone have any idea what's wrong with this car?
Thanks and have a great weekend.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That switch has three positions, ON all of the time, ON when the door is open, and OFF all of the time.
If the light always comes on when you select ON all of the time, then when it fails to come on with the door open, then the trouble is that the switch has been set to OFF all of the time.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks. I'll test it later. But the weird thing is, the light in the back seat doesn't turn off even I push that switch(button), once I have this kind of problem. I have to turn off the engine and pull out the key to turn the lights off. But when I don't have this problem, everything works normally. I push the button, all the lights turn on, and push it again, they turn off.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I just tested my daughter's car. If the front light fails to come on, but the back seat lights work, then I'b be suspecting a bad filiment in the failed lamp that is not completely broken off. A filiment can fail in a manner where it is intermittant, and I believe this is your problem.
There is no electrical reason inside the car that can make the lights work in the back seat but not the front.
PS I was incorrect on the operation of the switch. To get the Always OFF, you must press and hold the button for a few seconds, but in this mode the rear seat lights are also always OFF. In any mode where the rear lights come on, the front light also comes on. (I had forgotten that the E46 uses a push-button type of switch, and I described the rocker switch in my E36.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks a lot, Jeff. I'll check the bulb.
But I still wonder then why wouldn't the back seat lights go off until I pull out my car key when this strange thing is happening. When lights are working, all the lights go on/off when I press the button.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

delay circuit.

Probably because if the bulb is blown it confuses the delay circuit, which will run down a capacitor through the bulb.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for your detailed explanation, Mark.
Have a good weekend. :-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.