WARNING: TO PREVENT THE RISK OF HIGH-VOLTAGE SHOCK, ALWAYS FOLLOW PRECISELY ALL WARNINGS AND SERVICE INSTRUCTIONS, INCLUDING INSTRUCTIONS TO DEPOWER THE SYSTEM. THE HIGH-VOLTAGE HYBRID SYSTEM UTILIZES APPROXIMATELY 300 VOLTS DC, PROVIDED THROUGH HIGH-VOLTAGE CABLES TO ITS COMPONENTS AND MODULES. THE HIGH-VOLTAGE CABLES AND WIRING ARE IDENTIFIED BY ORANGE HARNESS TAPE OR ORANGE WIRE COVERING. ALL HIGH-VOLTAGE COMPONENTS ARE MARKED WITH HIGH-VOLTAGE WARNING LABELS WITH A HIGH-VOLTAGE SYMBOL. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

This pinpoint test is intended to diagnose the following:

low fan control (LFC), medium fan control (MFC), high fan control (HFC) relays
harness circuits HFC, LFC, MFC, VPWR
powertrain control module (PCM) (12A650)

Three Speed Fan Operation

Although the PCM output circuits are called low, medium, and high fan control (FC), cooling fan operation is controlled by a combination of these outputs.

Refer to ENGINE CONTROL COMPONENTS for system information.

Fig 1: Identifying Low Fan Control (LFC) Relay Connector

Courtesy of FORD MOTOR CO.

Chapter Navigation

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Pinpoint Tests KF: Fan Control (FC): Introduction

Use the Manual With the Right Hardware

When to See a Mechanic