CliffLS400

I have a 97 LS400 I bought for $400 due to blown air suspension (replaced with springs) and broken front passenger window, among other things. My most recent issues are almost identical to the post above, but began with this: Inoperable: Dome light, interior floor and overhead lighting, key fob, door locks (unless key in ignition and turned to on). steering column, adjustable mirrors Due to these issues, I purchased a new multiplex computer for the driver's side door). After installation, I reconnected the negative battery cable, started the ignition, and realized the lights on the driver's side door lock and window control were off. I then discovered the following were no longer working, in addition to the above: Inoperable: Sunroof, windows, door locks (even with key in ignition turned to on or full crank), trunk switch I suspected a fuse and determined the #21 "DOOR" fuse in the interior fuse box was blown. I attempted to replace it three times and every time, the fuse immediately blew. In the engine fuse box, I determined no current was passing through the following fuses (with the engine running): - "DOME-RR" 7.5 amp fuse - "MIR-HTR" 10 amp fuse - "SEC HORN" 7.5 amp fuse - "ECU-B" 15 amp fuse - "DOME-FR" 7.5 amp fuse I really would appreciate some guidance. From the posts I have read it could be the BODY ECU (if this is different than the Engine ECU I would like to know, as I had the engine ECU examined for capacitor issues and was told it is in perfect working order). It would be the door actuators, the locking mechanisms, sensors on the locks, etc.. Please advise, if possible.