2003 Acura RSX Base MT. Pulling my hair out and I ain't got much left! Lol...  I was having a rough idle but nothing crazy, for the last few years, figured it needed valve adjustment as it has just over 198k miles. I bought it new with only 4 miles.

Here's the issue, idle started surging. Idle control valve CEL came on. I changed it with a new one (cheap one) and there was no difference with Idle. Replaced it with a more expensive iacv and it was OK again. As I was  testing the the new valve the car died halfway out the drive way! Then I noticed the battery dummy light didnt come on while starting...  What the heck! Just put a new battery in it 2weeks before. I did some more testing and everything says it's the multiplex control unit (Basically the fuse box) but none of the usual symptoms of intermittent wiper, power lock, interior light issues with a bad mcu... I searched for a new box and even called the "dealer". Dealer said they dont have one and none in the USA! Again, what the heck.. (keeping it PG)

 So I swapped the alternator with 0-R1lies reman. for S and G's.  Now its charging doesnt die when driving but the battery light is on all the time!  Multimeter shows 14.3v with high beams etc. ON.  

I've got the RSX shop manual. I've even added extra ground wires to try to rule out a bad ground. 

Any ideas?

Thanks S.K.  for the honest videos, right wrong or indifferent, They've always helped!