2000 540i Tail Light Issue

[e39cttx]

Hi everybody, new to the forum so hope I'm doing this right. I have a 2000 540i and recently had a tail light start failing. Backstory is I believe 2000 was the last year the stock tail lights were halogens. Years ago I had them upgraded to LED which involved connecting the wiring to a transformer box (photo attached) made by Hella. After 15+ years, the passenger side box failed which brings me to my current predicament. In order to get the LED lights to work, I need to replace the transformer box, which is obsolete. I've scoured the internet and have been unable to find the transformer box. I found adapters that connect the conventional wiring to the LED lights, which make the lights work, but I am still getting the error code "Check Rear Light" and "Check Brake Light", plus the blinker hyperflashes due to the system not recognizing the current given off by the LEDs. Given I can not locate the transformer box, the only solution I see is to revert to the stock halogen lights with the orange lenses, which I am trying to avoid.