The assembly was ingeniously installed to light up only when the trunk door was open, and was not triggered by the central door open signal.
BHPian fluidicjoy recently shared this with other enthusiasts.
The Polo sold in India came without a boot-light, while internationally this car even got upto two boot-lights on either side. Polo enthusiasts have managed to artistically even install four trunk lights in their car, bright enough to probably read a book or cook dinner in their trunk, but I thought its imperative that I have at least one working light in place. There is a detailed DIY boot-light thread by Gannu, but it follows a different strategy than the one I ended up using. We also have a few other nice threads on boot lights which are worth reading.
Long ago, I bench tested a bright LED assembly and finalised its wiring. Ignore the messy wires, since they belong to multiple retrofits which were in the testing stage:
The assembly was ingeniously installed to light up only when the trunk door was open, and was not triggered by the central door open signal:
The key to doing this, is naturally using a special ground or power signal that knows when the boot is open or closed:
I took the positive connection from my footwell lights using one of these multiplier harnesses, and swapped the ground to a boot-position biased ground point, which I found on the left side of the car, on the rear left wheel arch:
Using a multimeter, find the ground point which receives continuity, when the boot is open and breaks contact when the boot is open, and you have your wire:
To keep things clean, I wrapped excess of my ground signal wire to the stock boot-ground pin, and taped the two from outside. Perfectly irreversibly, if I ever had to re-wire something or move things around, but I don’t see that happening anytime soon. I read about this trick on another Polo forum a long time ago. Last year, I told Prerak about this when he was in the process of wiring his boot lamp and he ended up making a very useful video implementing this trick while wiring and fitting two boot-lights, and I’ve linked his video at the end of this post. So, with this wiring, I had a perfectly functioning, super bright, boot light, but I got too busy to take out some time to cut a suitable rectangular slot for mounting this assembly in place. Prior to that, I had hung the boot-light on the luggage hook behind the rear seats and that illuminated more of the seat back than the boot itself.
Finally, this time, I got to it, with the worst set of tools, a kitchen knife and a candle, which I used as a heat source to hot slice through the plastic trim, but perseverance and patience helped get the job done. Here’s some pictures of the boot-light during the night. No extra processing has been done other than what smartphones are already doing today. With that, I complete another pending post that I have been wanting to write about.
Keyword: DIY: Installed a boot lamp in my Volkswagen Polo TSI AT