diy guide to installing a 2nd trunk light

[E30_(1st Musk)_]

^^ im down for 4 lights back there..

nice write up.

BDSax should do another one for the other 2 lights.

[Axxe]

Heatshrink buttconnectors >>> all. The only connection that's worth making.

[McGyver]

when i did this in my car i accidentally tapped into the 12v constant power instead of the ground. lawl, i burnt out a bulb before i realized what happened! (its fixed now)

[TomSuddard]

I added a second light, as shown above, a few years ago.

Well worth the 10 minutes of effort, and this write-up makes it even easier.

[iwantspeed]

I added a second light, as shown above, a few years ago.

Well worth the 10 minutes of effort, and this write-up makes it even easier.

yes

[3ionCa]

Very good DIY, I will def try this then post the results!!!

[Rouvld]

What size t taps and crimp connectors did you use? I'm looking to order some but don't know the gauge size of the wire.

[MrPromax]

Been looking for this!


I'm a noob. I'm an E30 noob. So most of my questions will be glorious display of noobility. I apologize in advance.

I lurk no more.

[Das Delfin]

This has been probably the single best mod I've done for my car. The one thing that could make it better is dual LED lights!

it's like 16-18 gauge wire

[Cephas]

I wish the pictures for the 4 light setup still worked. I'm guessing LED's make this a million times better as well.

[iwantspeed]

Hello what pictures do you need I can maybe take one for you.

[Staszek]

Thanks for the DIY, I installed mine yesterday when I was finishing up my alarm install.

[iwantspeed]

Awesome it looks good

[Staszek]

Awesome it looks good

Thanks, I changed it slightly, I used the oem pin with new connector with one brown wire directly out of it to each light then a third brown wire to my alarm it was pretty clean I should have taken a pic.

Then I used a new connector from the power to the light so that I had a secondary line come out of the back of the first light over to the second.

It makes such a difference in how much more light is in there!

This coming from a car that when I bought it had zero lights working, trunk or interior.

[BMWBob]

But what is that 3rd wire

I found that my trunk light was staying on. Thought it might be a bad switch. Nope.

The switch is used to connect the bulb to ground when the lid is open. The wire from the switch to the light has a tee tap. I found that that tee tapped wire is grounded, thus completing the circuit regardless of whether the switch is open or closed.

That wire is NOT shown on any BMW E30 325ix drawings. (I have the official 1989 BMW 325ix Electrical Troubleshooting Manual). The 5th and 6th pictures in the original post of this thread show the tee tap. See my labeled photo below.

Another way to ask the questions is: What other component or system needs to know when the trunk lid is open or closed? That is what that wire is doing – going negative/ground when the lid is open and going open when the lid is closed.

The type of connection makes me think it might be an after-market add on.