Cooling fans?

On my sons 1995 grand price with a 3.1 v-6 the drivers side cooling fan works with the a/c running but we cannot get the passenger side fan to run.
We have replaced the sensor next to the thermostat, fan motor and the relay located in the fuse box under the hood. Is there more relays and if so where?
Please help if at all possible. Thanks

[olopezm]

Powertrain Control Module (PCM) uses primary and secondary electric cooling fan relays to control primary and secondary cooling fans. Secondary cooling fan is used on vehicles with heavy duty cooling with A/C. PCM will energize primary cooling fan when Engine Coolant Temperature (ECT) sensor indicates greater than 223°F (106°C); A/C is requested and vehicle speed is less than 50 MPH; A/C refrigerant pressure is greater than 185 psi (13 kg/cm2 ); Diagnostic Trouble Codes (DTC) 14, 15 or 70 are set; or PCM is operating in back-up mode.

PCM will energize secondary cooling fan when ECT sensor indicates a temperature greater than 235°F (113°C) with A/C off or on, A/C is requested with vehicle speed less than 40 MPH, or A/C refrigerant
pressure is greater than 136 psi (9.6 kg/cm2 ).

Oscar.

If I was a mechanic that would probably help me understand it a little easier. Could it be the temp gauge is erratic and not working properly? Where is the sensor located that controls the temp gauge?

[gmtech1]

Is the car overheating? The info I have states that the secondary cooling fan will only operate if the the coolant temp is above 235deg a/c on or off (as stated above) OR if the a/c pressures are above 236psi (typo above) and speed is less than 50mph and will shut off when temp reaches 228deg, a/c pressures are less than 185psi or the key is turned off. The car just may not be getting hot enough to turn on the fan. A scanner with pcm output controls would be able to command on the fan and verify operation and check coolant temps as read by the pcm.

[olopezm]

Just like GMtech1 said or in other words, one fan will work on a more regular basis depending on the engine temperature, AC on/off or if there is a problem with engine components (bad ECT for example).

The other fan will work when the temperature reaches 235F or you've been idling for extended periods of time in traffic.

Oscar.

Okay. We pulled the wires off the temp sensor switch that goes in near the thermostat housing and the passenger side fan started working. We replaced that sensor and then plugged the wire back and so far no fan.
Now it will trip the CES and when you place it in gear the CES will go off. ???

[gmtech1]

You REALLY need a scanner so you can see what the actual coolant temp is, and now to see what code is set and clear it.