2001 malibu 3.1 v6 cooling fans run all the time and temp gage

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

mine is doing same thing have changed heat sensor the cooling fan runs all the time and check engine light is on i had it read and thay said the computer is not getting coolant temperature

Not computer. You have air in the cooling system. Bubble is moving around. Park on an upward incline, take the radiator cap off, run the engine and keep the radiator full. Let it warm up and let the thermostat open (until you see flow in the radiator). Then fill to the brim and keep full until it stops going down. Also open any bleed ports you can find in the cooling system (there may not be any) and let any air out of them. Let the engine run and check for any bubbles that continue to come out. If bubbles continue to come up, you have a blown head gasket that is forming the bubble and causing the heater and temp gage issues. If bubbles do not come out, maybe you have fixed the problem by getting all the air out. Please let me know if you have any questions.

your gage has just gone out and needs to be replace. the computer control the fan. so as long as the temp sensor is connected to the engine it will work fine but you will not know the temp of your vehicle.

country driving at high speeds keep engine air cooled. but in city there is not much air to cool the engine. check the sensor for the fans. relay for fans must be ok, cause you said if you disconnect sensor then fans run. replace fan sensor. also make sure there is a proper amount of coolant in system. (do this first).

I recommend replacing the thermostat and before installing it, drill a small hole in the center of the flat seating surface to bypass coolant during warm up. This will help to gradually warm the engine and it can save you some damage to the engine if the thermostat sticks. Mine did the same thing which sounds like the thermostat is sticking closed. My temperature needle goes from 1/2 to 3/4 max which is ok. Turn on your a/c and it should engage the electric cooling fan which will also save your engine from overheating. You may have a defective fan clutch.

The cooling fans are designed to come on at about 215 degrees to 219 degrees,and I have seen them come on at 225 degrees,the engine is designed to average 232 degrees at the most,it may not be warm enough to come on the first time,but the thermostat,if stuck will prevent this also,and you need to bleed the air out of the cooling system.

Check the cooling fan, its sensor, the relay, the fuse. On most cars the fan is not needed on the highway, but engine overheats it it doesn't switch on inside the city. Also, clean the system with a special liquid according to the directions on the can and use coolant after that, water causes corrosion. While pouring/filling/cleaning, keep the heat switch on max heating to allw circulation via the heating radiator.

Sounds to me that the temp sending unit needs to be checked or replaced, bad sending unit can cause a multitude of problems.... ie Fan not running, Engine running rough, Try checking for voltage at the sending unit with the ignition on but not running. Possibly bad sending unit.. Unit is usually located near the radiator hose that goes into the engine. usually round nut with either 1 or up to as many as 3 or 4 wires coming out of it Check the voltages there.. If you dont have power going in and nothing going out when the engine is warmed its bad.,...

The sensor is located at the radiator. follow the wire from the fan to the plug on the sensor. I hope this helps.