PINPOINT TEST KF: Fan Control Relays: Introduction

This pinpoint test is intended to diagnose the following:

low and high FC relays
harness circuits: LFC, HFC and VPWR
powertrain control module (PCM) (12A650)

Two Speed Fan Operation

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

Refer to ENGINE CONTROL COMPONENTS .

Fig 1: Identifying Cooling Fan Motor Connector

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Low Fan Control (LFC) Relay Connector

Courtesy of FORD MOTOR CO.

NOTE: The VPWR and LFC circuits may be reversed in the harness connector. Also, the LFC circuit may be wired to two separate relays. Refer to the appropriate System Wiring Diagrams article for additional information.

Fig 3: Identifying High Fan Control (HFC) Relay Connector

Courtesy of FORD MOTOR CO.

NOTE: The VPWR and HFC circuits may be reversed in the harness connector. Also, the HFC circuit may be wired to two separate relays. Refer to the appropriate System Wiring Diagrams article for additional information.

Powertrain Control Module (PCM) Connector

For PCM connector views or reference values, refer to REFERENCE VALUES article.

Vehicle	Pin	Circuit
F-150 3.5L	B23	HFC
F-150 3.5L	B4	LFC
Fiesta	B13	LFC
All other vehicles	B18	HFC
All other vehicles	B34	LFC