1997 Chevy Malibu cooling fans problem

Engine coolant temperature sensor may be bad .

Could you give more detail as to what it's doing exactly? Is it having a hard time cranking the engine or does the engine crank but not want to get started?

Cooling fan switch ? The cooling fans (2) on that motor are controlled by three relays . A coolant temp. sensor gives temp info to the PCM - engine computer .
During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM supplies a ground path for the cooling fan 2 relay and the cooling fan S/P relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan S/P relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.
The PCM commands Low Speed Fans on under the following conditions:
• Engine coolant temperature exceeds approximately 106°C (223°F).
• When A/C is requested and the ambient temperature is more than 50°C (122°F).
• A/C refrigerant pressure exceeds 1 310 kPa (190 psi).
• After the vehicle is shut off if the engine coolant temperature at key-off is more than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.
The PCM commands High Speed Fans on under the following conditions:
• Engine coolant temperature reaches 110°C (230°F).
• A/C refrigerant pressure exceeds 1 655 kPa (240 psi).
• When certain DTCs set .
Watch this video ,it shows how it works !
Relay Driven Dual Cooling Fan Diagnostics

The PCM controls that activation of the cooling fans. I uses three relays to do this. The configuration of the relays is such that failure of any one of them should not result in total fan failure (one or both would still operate). Try this - with the engine running, turn on the A/C. If the fans work, then your problem is that the coolant temp sensor is not telling the PCM the coolant temperature properly. If they still don't work, then, although it doesn't seem likely, I would have the COOLING FAN RELAY, COOLING FAN RELAY 1, and MODE CONTROL RELAY checked. Reason being that the only other possibilities are the PCM and the circuit wiring itself.

There is a sensor on the top of the engine which turns the fans on. it is usually located near the thermostat housing but dont confuse it with the temperature sensor which can easily be tested in the same means by watching the temperature gauge as you ground it out. it may take several seconds to indicate it on your sensors.
If you by-pass and hook the fans up direct without an in-line fuse and there is resistance in the line from a bad fan motor you will melt the wires and the fan motor itself. Use a 30 or 40 amp fuse inline and put on a switch if you like but don't hook direct but only for a few seconds or so to see if is working well. Use very thick wire like booster cable wire.

Take the lead off the sensor and contact it to the ground on the engine. If the fans start up with car running even cold then replace this sensor.
If not check relay by switching with same numbered relays typical in most vehicles. Mark the original relay and note it's position, take pics if you like to aid in placement.

East Coast Canada Rules.
Good luck!

CHECK THE THERMOSTAT. THERMOSTAT IS THE ONE THAT SENSE THE ENGINE TEMPERATURE AND TURNS ON COOLING FAN WHEN THE ENGINE IS HOT.

Cooling Fan Operation
The Electronic Control Module (ECM) regulates the voltage to the cooling fan relay. The relay operates the fan when the engine coolant temperature exceeds 106°C (223°F) The cooling fan will turn on automatically during extended idle conditions under 5 miles per hour. For diagnosis and location of the relay, refer to Electrical Diagnosis.

Relay Driven Dual Cooling Fan Diagnostics

Electric Testing Techniques You Need to Know
Do you know what a wiring diagrams is ? free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine ! Under system click on engine then under subsystem click on cooling fans . Click the search button then the blue link .

Test the electrical circuits before replacing parts !
Basic Electricity for Service Techs Ohm law Current Flow Opens Shorts
How to Use Multimeter to Troubleshoot Common Problems

Yes, you could wire them to run anytime the ignition is on, but that is not a good idea. Have you checked the fuse? Have you checked to see if the fans actually work? Turn the A/C on and one fan should run continuously. Have you replaced the thermal relay for the cooling fan? You need to just find out why they do not work. Running them continuously is not a good idea. You want the engine to reach full operating temperature as soon as possible. And you do not want to be constantly cooling it down by running the fans all the time. This will cause poor fuel mileage.

check the coolant level in the radiator it may be low
and starving the heater core

replace thermostat, this fixed my car, cooling fans keep coolant below temp guage parameters.