I found this post by Fred (Injuneer) on another forum. Sounds like the problems are similar, you might want to try this.
QUOTE
I ***think*** the Monsoon is similar to the Delco 2000 unit that was used in the early 4th Gen Firebirds. The "sub"-woofers next to the rear seats are run off a small module that tucks into the inside of the plastic sail panel near the floor. The sub-woofers are on a separate ciruit and do not run in parallel with the door low frequency drivers. If the wiring does not supply the signal and possibly power to the module in the sail panel, the subs are not going to work.
Just guessing.... but I suspect the "Monsoon" is either just a renaming or a few minor revisions to the Delco 2000 system.