Chart C-12D Cooling Fan Check (No High Speed Fan)

Cooling Fan Diagnostic Chart:

A/C Head Pressure Switch Wiring Schematic:

CIRCUIT DESCRIPTION
Power for the fan motors comes from a 40A maxifuse element to terminal "30" on the relays. The relays are energized when current flows to ground through the Powertrain Control Module (PCM) Quad-Driver #4. The left fan has two speeds and the right fan is a single speed fan.
^ Low Speed (Fan 1) Relay - The PCM energizes the relay through terminal "WD11" when engine coolant temperature reaches 100°C (2l2°F) or when Air Conditioning (A/C) is requested.
^ High Speed (Fan 2) Relay - The high speed relay is energized by the PCM if the A/C refrigerant pressure fan switch opens, indicating refrigerant pressure above 1448 kPa (210 psi), or engine coolant temperature reaches 108°C (226°F).