Cadillac Forum - Enthusiast forums for Cadillac Owners - Digital Dash Not Working. Need Insight. (New to this Forum. Hello all)

Hi, I'm hoping I get some quick help with this. I bought a 1990 Cadillac Sedan Deville and the Digital Dash doesn't work. Here's the sequence of what I noticed and tried.
1. purchase of car. noticed dig dash not working, nor Fuel Area or Climate Control area.
2. Researched the problem, including what was said/advised in this forum. Can't do the "reset" thing such as "pressing the Off and Warm buttons at same time." or the "disconnect Battery to reset." - No codes show up at all no matter what.
3. research further pointed out high probability that the BCM is bad.
4. Went to Pick A Part. Pulled a BCM from an intact similar Deville in attempt to save some money. Also pulled that car's ECM as well.
5. Took out my BCM and installed the BCM that I bought. (Did not switch PROMS).
6. Turned the key to ON position and Digital Dash came on. Started car. Pushed the OFF and WARM buttons on the climate control center and saw some codes scrolling in Fuel display area. I was so jazzed, until a couple of minutes later the dig dash LED started blinking then fading, then died all together. I turned off engine. Tried to restart engine. and nothing happened. Everything died.
7. I put my PROM into the BCM I bought. Disconnected Battery then reconnected. Still nothing. Car dead.
8. I put the PROM from BCM I bought into my BCM. Reconnected Battery. Car still dead.
9. Put my PROM back into my BCM and reinstalled/connected my BCM back into the car. Reconnected Battery. Car started, but dig dash still not working. Another weird (at least to me since this is my first time owning a caddy) thing I noticed is that, before I did anything with regards to the BCM...that altho the dig dash wasn't working, the fuel button lights and the climate control button lights would come on. Yet, after I did the BCM things, now those button lights don't come on, and the radio clock is dim instead of strong.

So...I need some advice as to what to do. I can't reset anything nor get codes since it doesn't show. I thinking that I need to invest in a new BCM from a retailer. Yes? If so, where's a good (not too expensive) retailer(s)?

Thanks for all your advice and input into my deville dilemma.

James (emailing me is quickest way for me to get info Satori_Warrior@Elitemail.Org)