Define what is missing
Check whether both lamps fail, only one side fails, or the fog-lamp indicator is the only abnormal function.
LIGHTING · 2002
2002 Firebird Fog Lamps Inoperative Diagnosis
Both fog lamps dead, one lamp dead and an indicator complaint have different factory diagnostic paths.
APPLICATION: 2002 Pontiac Firebird / Formula / Trans Am with the factory system described. Match options and installed hardware before applying a circuit path.
Check lighting-system context
Verify the headlamp/lighting state required for normal fog-lamp operation and look for other lighting symptoms before opening the circuit.
Prove relay/output and lamp branches
Use the applicable domestic Pontiac lighting diagram to separate switch/control, relay/feed and individual lamp/ground faults.
DO NOT REPLACE BOTH LAMPS FIRST
A shared control/feed fault can take out both lamps. One failed side points farther downstream.
FPV RULE
OBSERVE → MEASURE → ISOLATE → PROVE → REPAIR → VERIFY. A symptom is a starting point, not a parts verdict.
AFTER THE FAILURE IS PROVEN
Use the proven failed branch—not the original symptom—to choose the replacement. Go from diagnosis to the Parts Verdict →