I checked the Helm website, but they dont' have any wiring diagrams available for bonnevilles..
Not exactly what the intent was--Helm, Inc is the company that manufactures the Factory Service Manuals (FSM) for many vehicles. They will sell these manuals to the average person off the street (so to speak) but they are a little pricey--I think around $120 a set? Maybe higher?
Keep an eye out on ebay--I've picked up a full set for each of my cars:
96 Bonneville: $45
97 Grand Prix: $40
91 Bronco: $15
76 Datsun 280Z: $80 (yeah, they're a little harder to find)
It may take a while before you see them show up, but it seems like they eventually always do