1995 LT1 Cooling-Fan Diagnosis
Use the exact 1995 series/parallel fan architecture and exact factory command temperatures before condemning fan hardware.
Know the architecture
The 1995 system uses three relays. Relay 1 produces series low-speed operation; all three relays energized produce parallel high-speed operation.
Exact 1995 command points
Factory information states low speed ON at 108°C (226°F), OFF at 105°C (221°F); high speed ON at 113°C (235°F), OFF at 110°C (230°F).
A/C changes the test state
The factory diagnostic notes that the cooling fans should run when the A/C system is operating. Record A/C request and operating state before judging fan behavior.
Modified-car checkpoint
PCM tuning or aftermarket fan wiring can change when and how the fans run. Diagnose the configuration actually installed.
DO NOT REPLACE YET
Do not condemn the motors because they do not run at a lower temperature than the stock calibration commands.
Verification trail
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 →
DO NOT REPLACE YET
Do not replace a fan motor, relay, PCM or temperature sensor because the fan does not run in one condition. Follow the exact-year command-versus-response path and prove where the command or current path stops.
PARTS VERDICT
Replace the fan/relay/sensor only when its exact branch fails. If scan-command, wiring, power, ground or temperature-input evidence points elsewhere, repair that cause instead.
REPAIR → VERIFY
Heat-cycle or command the system through the original failure condition, verify the expected fan response returns and confirm the engine no longer overheats because of the same fan-control fault.
FPV DIAGNOSTIC RULE
SYMPTOM → TEST → ISOLATE → PROVE → PARTS VERDICT → REPAIR → VERIFY. A code, symptom or commonly failed part is not proof by itself.