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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
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Experience:  Have owned a repair shop for 25 yrs.
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92 chevy lumina: with a 3.1 liter engine the problem..cooling fans

Resolved Question:

i have a 92 chevy lumina with a 3.1 liter engine the problem it is having is that the cooling fans will not turn on
Submitted: 5 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 5 years ago.
you need to make sure the cooling fan fuse isnt blown.....check to make sure you get a ground signal from the computer to the #85 teminal at the relay when the cars temp is warm enough for the fan to come on,,remove and clean the terminals at the ecm[computer] ...if you dont get te ground signal to the relay coil#85,then,i would think the computer itself may be bad

92 Chevrolet Lumina V6-191 3.1L
Radiator Cooling Fan Motor Relay Description and Operation, Components: Cooling Fan Relay


The electric Cooling Fan is used for engine and A/C condenser cooling and is controlled only by the ECM.

Battery voltage to operate the cooling fan motor is supplied to relay by CKT 2. Ignition voltage to energize the relay is supplied to relay by CKT 650. When the ECM grounds CKT 335 the relay is energized and the cooling fan is turned "ON." When the engine is running, the ECM will turn the cooling fan "ON" if:

^ A/C is "ON."

When the engine is running, the ECM will turn the engine cooling fan "ON" for any of the following reasons:

^ Diagnostic Trouble Code (DTC) 14 is set.

^ Engine coolant temperature is 106°C (223°F) or greater.

^ A/C refrigerant pressure is 51 psi or greater with A/C selected and a Diagnostic Trouble Code (DTC) 66 is not set.

Once the cooling fan is enabled, the ECM will turn the fan "OFF" when:

^ Engine is turned "OFF."

^ Engine coolant temperature drops to 99°C (210°F) or less.

^ A/C refrigerant pressure drops to 41 psi or less with A/C selected.
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