Ambient Dome Light Instructions

A very elaborate and precise mod!
Not for the faint of heart though

Did you by chance evaluate the modifications required to install that E38/E39 domelight cluster?

Not meaning to rub sth into sth... the E31 domelight can also be had in very purdy black

8er.org/forum/index.php?attachment/21740/ 8er.org/forum/index.php?attachment/21739/

In my opinion the ambient lighting ought to make things visible that are otherwise in the dark. As such I´d probably not point the lighting towards the upper dash - all units located there have their own light source anyway. What does it look like if you reinstall the domelight the other way round?

Cheers
Reinhard

Great job Fern and excellent documentation ! I do however agree with Reinhard that you should perhaps experiment a bit with the aim of the ambient LEDs...

Zitat von reinhard;109841

Did you by chance evaluate the modifications required to install that E38/E39 domelight cluster?

Auraraptor and I experimented with the E38/E39 dome light in the E31, but it's not as easy as it may seem...

I don't really like the E31/E32 dome light. The switches feel and sound cheap and it looks dated. The E38/E39 dome light has a much better switch construction and a nicer design. When Auraraptor came up with the idea I went ahead and got myself an E38/E39 dome light. Its connector is different but that can be overcome with an adapter cable. Another issue is that the E31/E32 dome light has a common positive terminal whereas the E38/E39 dome light uses a common ground. Because of the polarity of the ambient LEDs you cannot simply switch polarity but the fix is very simple:

The resistor/dimmer is not required. The diagram was drawn before I noticed there's already a current-limiting resistor between the LEDs in the dome light. The result:

The only change is the yellow wire that connects the pin 1 copper plane with the cathode lead of the LED. Note that the middle switch of the E38/E39 dome light (Smid) is not connected in the diagram. That's because the middle switch is not a latching type but a momentary push button. The switching logic for the middle light is in the E38/E39 general module. In other words you cannot manually operate the middle light. I designed a small electronics board that restores full functionality of the E38/E39 dome light middle switch, but it's not shown in the diagram above. So electrically the result was 100% working and compatible with the E31.

On to installation in the car... And that's where we got stuck...

I knew the dimensions of the E38/E39 dome light were a bit different from the E31/E32 dome light, but I thought I could get away with a few simple modifications. The E38/E39 dome light is considerably less wide, a few millimeters higher and thicker. Less wide meant openings left and right. I was going to cover those gaps with headliner material from a spare sunroof motor cover. However, when I received my brand new cover from BMW it turned out to be in a different color than mine. As you know it turns out there's an error in the ETK and while there's probably a pile of Silbergrau Hell covers somewhere in a BMW warehouse, you can't order them... Bummer. Next issue: the extra (lateral) height. In the E31 there's a thin metal beam that "separates" the dome light area from the sunroof motor compartment and the extra height of the E38/E39 dome light prevents it from being installed. You cannot remove the beam because the sunroof cover needs it and while the E31/E32 dome light is clamped on the left and right side, the E38/E39 dome light clamps on the front and rear and thus requires the beam as well. The solution is to make a slot in the dome light enclosure, but that slot would run right through the clamps of the dome light face and also make installation and especially removal quite difficult... In the end it didn't seem worth all the effort and now, several years later, the E38/E39 dome light is still sitting on my bench :).

Guys... i really hate you both... Now i "NEED" to do this at my car !!!!

Now seriously... excellent writeup and excellent explanation about how to proceed with the E38 approach