I couldn't find anyone making these anymore and there was a big thread where a couple of amazing members here figured out the exact connectors to build them. I took their work and built 6 pairs since there was a minimum I basically needed to order in order to make it worth it to pay for shipping. There are 2 per car (1 for front, under the phone charger and one at the rear HVAC vent). Anyway, I'm selling the other 10 individual adapters I made and won't be making more so here's your chance.
I've tested each adapter to ensure it works with my personal car. Each one gives me the 9V/3A for 27W as expected. Each adapter built with 20 gauge stranded copper wire and I'll ship anywhere in the USA. $15/adapter + ship. Local pickup for free if you're anywhere near San Jose, CA