I have a Chilton'* manual that has a wiring diagram for the 92 Bonneville it doesn't say what models it covers. Hopefully the exterior lighting is the same on all models.
Wiring connector to the light switch should have power from two sources. The orange & red wires should both have 12 volts. The orange wire (for taillights?) is protected by fuse #14. The red wire (headlights?) is shown as coming from the battery with no mention of being protected by a fuse. It may have a fusble link built into the wire.
Check those 2 wires for power & report your findings.
1999 Pontiac Bonneville SSEi (son'*)
1997 Chevy Lumina (daughter'*)
2006 Chevy Trailblazer (wife'*)
2006 Chevy Monte Carlo SS (Mine! -Zoom Zoom Zoom)