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2.6 Radiator Fan

GM 84100128 Camaro Electric Fan

Type: Electric radiator fan

Model: GM 84100128

Manufacturer: General Motors

Product Page: GM Parts Direct 84100128

Mounting: Radiator shroud

Power Source: PMU OUT2+3+4 combined (75A capacity)

Overview

Brushless PWM electric fan with automatic temperature control via PMU24. J1939 CAN bus coolant temp (SPN 110) drives PMU PWM output.

Specifications

  • Current: 53A @ full speed, 32A @ 60%, 16A @ 30%
  • Airflow: 4188 CFM installed, 5690 CFM free air

Temperature Control

Coolant Temp Fan Speed PMU Duty Cycle Current
<185°F OFF 100% 0A
185-195°F Low (30%) 70% ~16A
195-205°F Medium (60%) 40% ~32A
≥205°F Full (100%) 10% 53A

Inverted Duty Cycle

GM brushless fans use inverted duty cycle - high duty cycle = low fan speed. PMU programming must account for this inversion.

Wiring

Circuit Wire Gauge Source Destination Notes
Fan Power (PMU side) 12 AWG × 3 PMU OUT2, OUT3, OUT4 Splice near PMU PMU 2.8mm terminals max 12 AWG
Fan Power (load side) 4 AWG Splice Fan motor (+) ~6 ft, ~1.2% drop @ 53A
Fan Ground 4 AWG Fan motor (-) Engine Bay Bus Short run

Wire Transition: PMU terminals accept max 12 AWG. Three 12 AWG wires from OUT2, OUT3, and OUT4 splice into a single 4 AWG wire near the PMU (not the fan) to minimize voltage drop - 4 AWG for the long run is better than 3× 12 AWG in parallel.

See PMU Outputs for complete configuration and PMU Programming for control logic.

Outstanding Items

None - design complete. See installation checklist for build tasks.