Radiator fan - Revision history

Cliff at 23:54, 18 July 2026

2026-07-18T23:54:30Z

← Older revision		Revision as of 23:54, 18 July 2026
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	On air-conditioned cars, the radiator fan may run when the air conditioning is selected.		On air-conditioned cars, the radiator fan may run when the air conditioning is selected.

	On ~~1988~~ ECM-controlled ~~applications~~, the ECM ~~can turn on~~ the fan when an A/C request is present. The A/C clutch does not necessarily have to be engaged for the fan request to occur.		On ECM-controlled systems, the ECM may command the fan on when an A/C request is present. The A/C clutch does not necessarily have to be engaged for the fan request to occur.

			Other fan-control arrangements may use different A/C request or pressure-switch logic, depending on year and equipment.

	If the fan works with air conditioning but not from temperature control, the fan motor and part of the relay/wiring circuit may be functional, while the temperature-control side still needs diagnosis.		If the fan works with air conditioning but not from temperature control, the fan motor and part of the relay/wiring circuit may be functional, while the temperature-control side still needs diagnosis.
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	== Coolant sensor failure mode ==		== Coolant sensor failure mode ==

	On ~~1988~~ ECM-controlled ~~applications~~, a coolant sensor failure can cause the ECM to command the cooling fan on continuously.		On ECM-controlled fan systems, a coolant sensor failure can cause the ECM to command the cooling fan on continuously.

	This may occur when diagnostic trouble Code 14 or Code 15 is set.		This may occur when diagnostic trouble Code 14 or Code 15 is set.

			This behavior should not be assumed for earlier switch-controlled fan circuits.

	Related topics:		Related topics:

Cliff: /* Temperature-controlled operation */

2026-07-18T23:52:38Z

Temperature-controlled operation

← Older revision		Revision as of 23:52, 18 July 2026
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	The radiator fan is intended to run when coolant temperature becomes high enough that extra airflow through the radiator is needed.		The radiator fan is intended to run when coolant temperature becomes high enough that extra airflow through the radiator is needed.

	~~On 1988 ECM~~-~~controlled applications~~, ~~the ECM commands the fan relay on when coolant temperature is above approximately 108°C / 230°F. The fan is commanded off again when temperature drops to about 101°C~~.		Fiero fan-control strategy depends on model year, engine, and equipment.

	~~Earlier~~ systems ~~and different engine configurations may~~ use a coolant temperature fan switch ~~rather than~~ the ~~same~~ ECM-controlled ~~strategy~~.		Some systems use a coolant temperature fan switch to operate the radiator fan relay when coolant temperature exceeds approximately 230°F / 110°C.

			ECM-controlled systems use the ECM to provide a ground path for the fan relay. In this arrangement, the ECM commands the fan on when coolant temperature is above approximately 108°C / 230°F, and turns the fan off again when coolant temperature drops to about 101°C.

	A fan that does not run until a high indicated temperature does not automatically mean the fan system has failed. The factory fan-on temperature is relatively high compared with normal thermostat opening temperature.		A fan that does not run until a high indicated temperature does not automatically mean the fan system has failed. The factory fan-on temperature is relatively high compared with normal thermostat opening temperature.

			Because the Fiero temperature gauge, warning light, fan switch, coolant temperature sensor, and ECM control circuit are separate or partly separate depending on year and equipment, diagnosis should use the correct wiring diagram for the specific car.

	== Air-conditioning operation ==		== Air-conditioning operation ==

Cliff at 23:51, 18 July 2026

2026-07-18T23:51:16Z

Show changes

Cliff: Created page with "'''Radiator fan''' refers to the electric cooling fan used at the front radiator of the Pontiac Fiero. The radiator fan helps pull air through the radiator when vehicle speed or natural airflow is not enough to keep coolant temperature under control. == Overview == The Fiero radiator is mounted at the front of the car, while the engine is mounted behind the passenger compartment. Because of this layout, the cooling system uses long coolant pipes between the engin..."

2026-07-06T20:39:45Z

Created page with "'''Radiator fan''' refers to the electric cooling fan used at the front radiator of the Pontiac Fiero. The radiator fan helps pull air through the radiator when vehicle speed or natural airflow is not enough to keep coolant temperature under control. == Overview == The Fiero radiator is mounted at the front of the car, while the engine is mounted behind the passenger compartment. Because of this layout, the cooling system uses long coolant pipes between the engin..."

New page

'''Radiator fan''' refers to the electric cooling fan used at the front radiator of the [[Pontiac Fiero]].

The radiator fan helps pull air through the radiator when vehicle speed or natural airflow is not enough to keep coolant temperature under control.

== Overview ==

The Fiero radiator is mounted at the front of the car, while the engine is mounted behind the passenger compartment.

Because of this layout, the cooling system uses long coolant pipes between the engine and the front radiator. The radiator fan is mounted at the radiator and is used to increase airflow through the radiator when needed.

A radiator fan problem can cause overheating, especially at idle, in traffic, or at low vehicle speed.

== Location ==

{{Image wanted|Photo or diagram showing the Fiero radiator fan location at the front radiator, plus fan relay and fan switch locations if possible.}}

The radiator fan is mounted at the front radiator.

The radiator itself is located at the front of the car, behind the front fascia area.

The fan is part of the front cooling-system assembly, not the engine-compartment assembly.

== Function ==

The radiator fan moves air through the radiator when airflow from vehicle movement is not enough.

The fan is especially important during:

* Idle
* Slow traffic
* Hot weather
* Extended low-speed driving
* Air-conditioning use, if equipped
* Cooling-system diagnosis

== Fan control ==

Radiator fan control depends on year and equipment.

The fan may be turned on by a temperature switch, ECM control, air-conditioning request, relay circuit, or related wiring depending on the model year and configuration.

Because fan-control details can vary, diagnosis should use the correct wiring diagram and service information for the specific car.

Related topics:

* [[Radiator fan switch]]
* [[Radiator fan relay]]
* [[ECM]]
* [[Wiring diagrams]]
* [[Connector pinouts]]

== Common symptoms ==

Possible radiator-fan-related symptoms include:

* Engine overheats at idle
* Engine overheats in traffic
* Temperature drops when driving faster
* Fan never turns on
* Fan runs constantly
* Fan works only with air conditioning
* Fan fuse or relay problem
* Intermittent overheating
* Temperature gauge rises while stationary

== Common causes ==

Common causes of radiator fan problems include:

* Failed fan motor
* Failed fan relay
* Faulty fan switch
* Wiring problem
* Poor connector contact
* Blown fuse
* Poor ground
* Air-conditioning control issue
* ECM or control-circuit issue, depending on year
* Previous wiring modifications

== Diagnosis ==

Basic diagnostic checks include:

# Confirm whether the engine is actually overheating.
# Check coolant level and cooling-system condition.
# Check whether the fan turns freely.
# Check whether the fan runs when commanded or powered according to the correct test procedure.
# Check fan fuse and relay.
# Inspect fan wiring and connectors.
# Check fan ground.
# Check the fan switch or control circuit.
# Check whether the fan operates with air conditioning if equipped.
# Check the correct wiring diagram for the year and configuration.

== Relationship to overheating ==

A radiator fan problem often shows up most clearly when the car is stopped or moving slowly.

If the car cools normally at road speed but overheats at idle or in traffic, the radiator fan system should be checked.

However, overheating can also be caused by trapped air, low coolant, crushed coolant pipes, radiator problems, thermostat problems, water pump problems, or incorrect caps.

Related topics:

* [[Overheating]]
* [[Cooling system]]
* [[Coolant filling procedure]]
* [[Thermostat]]
* [[Water pump]]
* [[Coolant pipes]]

== Air conditioning relationship ==

On many cars, the radiator fan may run when the air conditioning is turned on.

If the fan works with air conditioning but not from temperature control, the fan motor and some wiring may be functional, while the temperature switch or control side still needs diagnosis.

== Notes ==

Do not assume the radiator fan is working just because the engine overheats slowly rather than immediately.

The fan should be tested directly if overheating occurs at idle, in traffic, or during low-speed operation.

Also do not assume every overheating problem is caused by the fan. The Fiero cooling system must be properly filled and free of trapped air.

== See also ==

* [[Cooling system]]
* [[Overheating]]
* [[Coolant filling procedure]]
* [[Radiator fan switch]]
* [[Radiator fan relay]]
* [[Thermostat]]
* [[Water pump]]
* [[Coolant pipes]]
* [[Temperature gauge]]
* [[Electrical system]]

[[Category:Fieropedia]]
[[Category:Cooling system]]
[[Category:Electrical system]]
[[Category:Diagnostics]]
[[Category:Common problems]]