Trying to make sense out of the center stack. 87-89 use a black on yellow-green LCD and LCDs of the era do not tolerate sunlight well. Looks like management is handles by backplane and most of the tasks (Reatta has same buttons right down to off-warm to get into diagnostics). Problem is that Delco-Kokimo seems to have subbed the stack to Yazaki and were made in Japan (alla them little white wires) something they don't mention in the brochure. Yazaki has been unresponsive to e-mails).
Meanwhile since acquiring a pair of Allantes last year have been fascinated by the stack, have a couple of decades of reprogramming Reattas so understand what it is doing, it is the how that is complicated.
Have an early and a late stack I've been disassembling and have it pretty much down to block diagrams but the schematics are difficult (see them little white wires). Know what is going on but not on exactly what wire. Also understand the LCDs, dual controller boards, and early backplane lighting, am thinking may be easiest to replace with a single Arduino and some modern LCDs (not sure whether 20 character or dot matrix yet).
If anyone has any schematics or diagrams of the center stack (Delco that to tell Yazaki what to do) it would be greatly appreciated.