Interior light Problem, Please Help.

[RearWheelDrift3r]

Well, i have a small electrical "glitch" on my car. My driver's side rear interior light keeps coming on by itself, even with all the 4 doors closed. The only way to make it shut off is by putting my key in the ignition and put the ignition in auxilary mode (forward) or even start the car, then the rear interior light switches off. It will then come on again on it's own.

Does it look like there is a bad ground somewhere, and is there anything i can check first before bringing it to a mechanic? The car in question is a 1987 325i 4 door. Thanks.

[ethree]

Have you checked the door switch? It could be loose, my lights don't come on at all unless I fiddle with the door/pressure switch.

[RearWheelDrift3r]

Have you checked the door switch? It could be loose, my lights don't come on at all unless I fiddle with the door/pressure switch.

I checked all the 4 door switches and they are corrosion free and "seem" fine. They all work (the door switches) well with the interior light, EXCEPT for when the interior light turns on by itself when the car is parked. Once the interior light turns on by itself i have to put my key in the ignition and turn forward, or i have to remove the bulb .

Please help. Thanks.

[DaveSmed]

There is likely a loose wire in your drivers door.

Big hint there is the light going off with the ignition. Your car has an illuminated entry feature that probably doesn't work any more. (most don't) It is supposed to turn the dome light on for 15-30 seconds when someone lifts up on the outside door handle. It automatically cuts off when the ignition is turned on. The relay that controls that is in the drivers side footwell, behind the speaker next to your central locking module.

Only thing I can't explain is why it seems to be affecting the one light. it should be all of the dome lights that normally come on when you open the door.

[RearWheelDrift3r]

Thanks DaveSmed for your post. Do you think that if i were to remove the relay that it would stop the light from coming on by itself? My interior switch for the rear passenger side is actually broken that's why it's not turning on with the other interior lights. So you think i should look for my problem in the drivers side door? Thanks again.

[DaveSmed]

Thanks DaveSmed for your post. Do you think that if i were to remove the relay that it would stop the light from coming on by itself? My interior switch for the rear passenger side is actually broken that's why it's not turning on with the other interior lights. So you think i should look for my problem in the drivers side door? Thanks again.

Unfortunately, If you were to remove the relay, the dome light wouldn't work with the driver's door anymore. However, what you can do is remove the relay and look at the bottom. Each pin is labeled. You are interested in the one labeled "1G". Cut the wire going to 1G and you should be set. Optionally, you can splice it into "TK" to restore the timer feature, leaving the wire that is shorting out in the door disconnected.

[RearWheelDrift3r]

Thanks again Dave for the advice, i really appreciate it. On Wednesday i am going to try out what you said and hopefully it will be fixed. I will let you know the outcome on Thursday.

Do you know how big the relay is or will i easily find it once i remove the panel?

[RearWheelDrift3r]

I forgot to mention that i have an alarm system on my e30, and when my car alarm is on & "armed" and the interior light turns on on it's own my alarm goes off...the alarm module "thinks" that a door was opened so the alarm just keeps ringing and ringing, that's why i want to find the problem so that i can continue to use the alarm system without it always going off. Thanks.

[gearheadE30]

Still sounds like a door switch to me. With 1 door open, try wiggling the switch. If the lights flicker, that's probably it. Try this on all of the doors. A lot of the badly-wired aftermarket alarms I have seen were wired to these switches, which is pretty stupid if you ask me. I can get into my car without the lights coming on...

[RearWheelDrift3r]

Hi gearheadE30. I will try what you suggested, one door at a time while i wiggle the switch. It's weird though...after hours of the car sitting the interior light comes on on it's own...grrrrrrrr i hate electrical "glitches"

[DaveSmed]

I forgot to mention that i have an alarm system on my e30, and when my car alarm is on & "armed" and the interior light turns on on it's own my alarm goes off...the alarm module "thinks" that a door was opened so the alarm just keeps ringing and ringing, that's why i want to find the problem so that i can continue to use the alarm system without it always going off. Thanks.

Alarm system huh. Well, that could be a whole other group of possibilities.

I would be hesitant to think it's a switch issue or loose wire issue simply because of how it interacts with the ignition. BUT both the timer relay and the alarm control the dome light and interact with the ignition circuit.

[RearWheelDrift3r]

***UPDATE***

Well, we dismantled the car yesterday and removed the relay like you suggested (DaveSmed) and everything appears to be ok now. The only thing that doesn't work is when i open the drivers side door, the interior light doesn't come on but all other 3 doors do. When i need to change a window motor or some other kind of work on my drivers side door i will fix the little electrical "glitch" at the same time. My friend thinks it's a bad switch behind the door handle. Thanks again for the help and solving my problem.