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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 15576
Experience:  Have owned a repair shop for 25 yrs.
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98 chevy malibu: overheating< fans will come..disconnect..reservoir

Customer Question

i have a 98 chevy malibu, I'm having problems with overheating< fans will come on high speed when i disconnect the coolant temp sensor , they will only come on low when the a/c is on and they will not turn when the car is hot. Take in consideration that i've changed the thermostat, coolant sensor twice and the reservoir . No milky oil. What do you think is the problem?
Submitted: 7 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 7 years ago.

hi

the problem may be the fan relay

thanks

Operation

The electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the Powertrain Control Module (PCM) . The cooling fan has one speed. The PCM turns the cooling fan on by grounding the coil of the cooling fan relay when certain conditions are met. When the A/C is requested, the cooling fan will also be turned on.

Operation

The electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the Powertrain Control Module (PCM) . The cooling fan has one speed. The PCM turns the cooling fan on by grounding the coil of the cooling fan relay when certain conditions are met. When the A/C is requested, the cooling fan will also be turned on.

Engine Cooling Fan Control

The engine cooling fan control is partitioned between the PCM and the BCM via class 2. The main algorithm control resides in the BCM. The BCM sends a fan speed command to the PCM. The PCM processes this command along with its own fan request. The PCM determines what the actual fan speed should be.


Locations
Radiator Cooling Fan Motor Relay
icon_note_blank.gif Notes Understood Junction Block (Part 1 Of 2)
icon_note_blank.gif Notes Understood Junction Block (Part 2 Of 2)
icon_note_blank.gif Notes Locations View

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