Since I had the time & was near it, I stopped in at the one local stealership's service department to try to ask some info on the W-body light switch & to see if my guess was correct. It was usless, all the desk jockey went on about was about the tech who would know gets paid by the job order, it'll cost shop rate to look at it, yada, yada, yada... I had to explain my theory & wanted to know if what I was thinking was on the right track. Told him I had the manuals, had everything functioning as designed, explained it didn't need a BCM just wanted to try to get the light feature. End result, he was usless & didn't understand the work being done.