PINPOINT TEST KF: Fan Control Relays: Introduction
This pinpoint test is intended to diagnose the following:
- CAC fan relay
- fan control (FC1, FC2, FC3, FC4, FC5) relays
- harness circuits: CACCF, FGC, LFC, MFC, HFC and VPWR
- PCM (12A650)
Although the PCM output circuits are called LFC, MFC, and HFC, cooling fan operation is controlled by a combination of these outputs.
COOLING FAN STATE
| PCM Output | Low Speed | Medium Speed | High Speed | |
|---|---|---|---|---|
| Vehicles With 5 Fan Control Relays | LFC | ON | ON | ON |
| MFC | OFF | ON | ON | |
| HFC | OFF | OFF | ON | |
| All Others | LFC | ON | N/A | ON |
| HFC | OFF | N/A | ON |
Harness Side
| Circuit | Pin |
|---|---|
| VPWR (Vehicle Power) | 1 |
| B+ (Battery Positive Voltage) | 3 |
| CACCF (Charge Air Cooler Cooling Fan) | 2 |
| FANPWR (Fan Power) | 5 |
Harness Side
| Circuit | Pin |
|---|---|
| FANPWR (Fan Power) | 1 |
| GND (Ground) | 2 |
Harness Side
| Circuit | Pin |
|---|---|
| FANPWR (Fan Power) | 1 |
| FC (Fan Control) | 2 |
Harness Side
| Circuit | Pin |
|---|---|
| FANPWR (Fan Power) | 1 |
| GND (Ground) | 2 |
Harness Side
| Circuit | Pin |
|---|---|
| VPWR (Vehicle Power) | 2 |
| B+ (Battery Positive Voltage) | 3 |
| LFC (Low Fan Control) | 1 |
| FANPWR (Fan Power) | 5 |
Harness Side
| Circuit | Pin |
|---|---|
| VPWR (Vehicle Power) | 2 |
| HFC (High Fan Control) | 1 |
| FANPWR (Fan Power) | 4 |
| FGC (Fan Ground Control) | 3 |
| GND (Ground) | 5 |
NOTE:
The HFC circuit may be wired to the FC3 and FC5 relays. Refer to the
Wiring Diagrams Manual for additional information.
Harness Side
| Circuit | Pin |
|---|---|
| VPWR (Vehicle Power) | 2 |
| B+ (Battery Positive Voltage) | 5 |
| HFC (High Fan Control) | 1 |
| FANPWR (Fan Power) | 3 |
NOTE:
The MFC circuit may be wired to the FC2 and FC4 relays. Refer to the
Wiring Diagrams Manual for additional information.
Harness Side
| Circuit | Pin |
|---|---|
| HFC (High Fan Control) | B39 |
| LFC (Low Fan Control) | B43 |