Cooling fan operation questions

[zul8tr]

I have searched for "cooling fan" and was not successful with the search results so heare is my case.

Some base info

I have a 98 I30 auto and the cooling system is in top shape. New OEM thermostat installed and checked on stove to verify correct open temp and amount of valve opening. No overheating issues both fans operate at low and high speed. Fluid changed each 18 months. All check temps measured with an infrared gun.

Per the FSM generally:

(1)With AC off Elec cooling fans will operate in low speed if coolant > 203 degrees F and in high speed > 230 F (I think 230 correct)

(2)With AC on the low speed fan is always on (<50mph) and high speed will come on for coolant >203 degrees F.

Questions:

(1) Is the temp signal provided for the 2 cooling fans operation from the coolant temp sensor?

(2) With AC on the cooling fans go into high speed with coolant temps at the coolant temp sensor < 203 degrees F (measuring 180 F +/- and at the thermostat location about 176 degrees F +/-. What can be defective with this high speed fan operation coming on with temps < 203 F? Is it a defective relay? What else can I check?

Thank you

[elwesso]

Moved this to the maxima forum.

[blownb310]

I have a Maxima with the two fans on all the time, no matter what, as long as the key is on.

What was the problem with your Max?

Mike

[loystock]

Which Maxima model year?

Cooling Fan Relay 1 is used for Low Speed Cooling while Cooling Fans Relays 2 and 3 are for High Speed Cooling. The ECM controls the ground (Pin 2) of the relay to turn it ON/OFF depending on the coolant temp, speed, and AC status.

Most likely you have a stuck (close) Cooling Fan Relay 1 (for low speed cooling) causing both fans to run at Low Speed with Ignition ON. Another possibility is that Pin 2 of the relay is shorted to ground or the ECM is continuously grounding it. Also possible is defective Coolant Temp Sensor causing the ECM to turn on the cooling fans.

Pull out Cooling Fan Relay 1 and the fans should turn off. Replace as required. Verify Pin 2 of the relay receptacle is not grounded. If so, you may have a problem with the harness, ECM or coolant temp sensor.