My new electric car (a BMW i3 REX) is chock full of cool technology, but it has one of the most anemic trunk lights I've seen in a while. I decided to upgrade it by adding a strip of warm white LEDs to the underside of the package shelf that covers the cargo area.

What you'll need:

Waterproof LED strip ( I used a warm white strip); The waterproof versions are top coated with a clear silicone that will help protect the LEDs if something in the trunk bumps them.

https://www.amazon.com/gp/product/B01339F5ZO/ref=o...

Molding tape - used to secure the LEDs to the underside of the shelf (I would not rely on the strip's own adhesive)

https://www.amazon.com/3M-03614-Scotch-Mount-Moldi...

Quick tap wire splices - makes it easy to connect to power and eliminates the need to solder connector to the car

https://www.amazon.com/Quick-Splice-Connector-22-1...

Polarized connector - I already had one (salvaged from a 12V light), but they're available online:

https://www.amazon.com/Sea-Dog-Polarized-Connector...

Wire

Soldering iron, heatshrink tubing, misc small hand tools

About an hour of time

Step 1: Power Up!

The current truck light pops out easily and can be removed from the power connector (first pic). I spliced into the light's wires using self-tapping splices https://www.amazon.com/Quick-Splice-Connector-22-1...

Step 2: A Little Light, Please

After trimming the waterproof LED strip to length, I soldered on a length of 2 conductor wire and covered the connection with heatshrink tubing. Next, I used 3M body molding (https://www.amazon.com/3M-03614-Scotch-Mount-Moldi...) tape to stick the LED strip to the underside of the package shelf, and more tape to secure the wire along the side of the shelf. I did this during the fall - we'll see if it holds up once summer temps start hitting the 90s.

Step 3: Connecting to the Trunk Light Circuit

After reinstalling the package shelf, I used a 12 VDC polarized connector so that the shelf can be removed for more cargo space. After recconnecting the wires to the "old" light, I reinserted it.

Step 4: Finished!

Here are the after & before pics. The new light makes a huge difference when accessing the trunk when I leave for work (always in the dark). Total time was < 1 hour.