Engine Cooling Fan: Other Pontiac Vibe I

COOLING FAN SYSTEM

The engine cooling fan system consists of an electric cooling fan, 2 fan relays and a fan resistor. The fan 1 relay controls power to the fan motor. The fan 2 relay controls the ground path of the fan motor. The gauge fuse supplies ignition voltage to the coils of both the fan 1, and the fan 2 relays. The RDI fuse supplies battery voltage to the switch side of the fan 1 relay. The PCM controls the ground for the coils of both relays. The PCM controls low and high speed fan operation by energizing and de-energizing the fan 2 relay which changes the ground path of the fan motor.

PCM Control

The PCM commands low speed fan operation when all of the following conditions occur

1. The A/C system is operating.
2. The A/C system pressure is below 178 psi (1226 kPa).
3. The Engine Coolant Temperature (ECT) is below 181°F (83°C).

The PCM commands high speed fan operation when either of the following conditions occur

1. The ECT reaches 199°F (93°C).
2. The A/C system pressure exceeds 220 psi (1520 kPa).

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. See INTERMITTENT OR POOR CONNECTIONS .

CHECKING AFTERMARKET ACCESSORIES

DO NOT connect aftermarket accessories into the following circuits

1. SIR circuits, all such circuits are indicated on wiring diagrams with the SIR symbol.
2. OBD II circuits, all such circuits are indicated on circuit diagrams with the OBD II symbol.

Always check for aftermarket accessories (non-OEM) as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems.

Possible causes of vehicle problems related to aftermarket accessories include

1. Power feeds connected to points other than the battery.
2. Antenna location.
3. Transceiver wiring located too close to vehicle electronic modules or wiring.
4. Poor shielding or poor connectors on antenna feed line.
5. Check for recent Technical Service Bulletins (TSB) detailing installation guidelines for aftermarket accessories.

INTERMITTENT OR POOR CONNECTIONS

Note. Tools Required: GM-Approved Terminal Test Kit (J-35616-C) Terminal Repair Kit (J-38125-D), Instruction Manual (J-38125-4) and Flat-Wire Probe Adapter (J-42675).

Most intermittent conditions are caused by faulty electrical connections or wiring. Inspect for the following items

1. Wiring broken inside the insulation.
2. Poor connection between the male and female terminal at a connector.
3. Poor terminal to wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself and corrosion in the wire to terminal contact area, etc.
4. Wire insulation which is rubbed through. This causes an intermittent short as the bare area touches other wiring or parts of the vehicle.

Round Wire Connectors

Follow the procedure to test terminal contact of Metri-Pack or 56 series terminals. Refer to the terminal repair kit or the instruction manual for terminal identification. Follow the procedure in order to test terminal contact.

1. Separate the connector halves.
2. Visually inspect the connector halves for contamination. Contamination may result in a White or Green build-up within the connector body or between terminals. This causes high terminal resistance, intermittent contact, or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals, and connector body.
3. Using an equivalent male terminal from the terminal repair kit, test that the retention force is significantly different between a good terminal and a suspect terminal. Replace the female terminal in question.

Flat Wire (Dock & Lock) Connectors

There are no serviceable parts for flat wire (dock and lock) connectors on the harness side or the component side. Follow the procedure below in order to test terminal contact.

1. Remove the component in question.
2. Visually inspect each side of the connector for signs of contamination. Avoid touching either side of the connector as oil from your skin may be a source of contamination as well.
3. Visually inspect the terminal bearing surfaces of the flat wire circuits for splits, cracks, or other imperfections that could cause poor terminal contact. Visually inspect the component side connector to ensure that all of the terminals are uniform and free of damage or deformation.
4. Insert the appropriate adapter from the flat-wire probe adapter on the flat wire harness connector in order to test the circuit in question.

Causes

1. Short to ground in the fan 1 relay coil control circuit.
2. Short to B+ in the fan motor supply voltage circuit.

Short to ground in the fan 2 relay coil control circuits.

1. Open or short to ground in the fan 1 relay supply voltage circuits.
2. Open or short to B+ in the fan 1 relay coil control circuit.
3. Open or short to ground in the fan motor supply voltage circuit.
4. Short to ground in the fan 2 coil supply voltage circuit.
5. Open or short to B+ in the fan motor ground circuit.
6. Short to B+ in the fan 2 coil control circuit.

Open or short to B+ in the fan resistor circuit.

1. Open in the fan 2 relay supply voltage circuit.
2. Open in the fan 2 relay coil control circuit.
3. Open in the fan 2 relay high speed ground circuit.

1. Short to ground in the fan motor ground circuit.
2. Short to ground in the fan resistor circuit.