Check both lamps
One side out and both sides out are different clues. Inspect bulbs/sockets only after recording the pattern.
LIGHTING · 2002
2002 Firebird Backup Lamps Inoperative Diagnosis
Backup lamps that stay dark need transmission/range-switch input, feed and lamp-circuit diagnosis before bulbs or switches are guessed.
APPLICATION: 2002 Pontiac Firebird / Formula / Trans Am with the factory system described. Match options and installed hardware before applying a circuit path.
Confirm the reverse input
Use the transmission-specific factory circuit path. Manual and automatic configurations can use different switch/range information.
Verify the circuit under command
With reverse legitimately selected and the vehicle safely secured, verify the input and output path without bypassing starter/interlock safety systems.
SAFETY GATE
Do not work around a running vehicle in gear. Chock/support as appropriate and follow the factory procedure for the transmission installed.
FPV RULE
OBSERVE → MEASURE → ISOLATE → PROVE → REPAIR → VERIFY. A symptom is a starting point, not a parts verdict.