2015 GMC Yukon XL Cooling fans not engaging

[MEA403]

I'm going crazy over this issue. About 4 weeks ago my AC stopped working, I had the system checked for leaks, there were none. I noticed when the AC is on the compressor clutch is engaged but the cooling fans behind the condenser aren’t engaging. The fans behind the condenser were replaced, compressor replaced, HVAC module reprogrammed and $1500 later the AC still blows cold intermittently. When the fans are turning I have cold AC and when they aren’t I get hot air. I've seen videos of the cooling gauge being a issue but my gauge is reading normal. I’m starting to lose faith in the dealer. Any thoughts?

 

[Ibustbravo]

Here you go.​

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Diagnostic Instructions​

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description​

The engine cooling fan system is composed of two electric cooling fans. The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control modules. The cooling fan control module varies the voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which enables cooling fan operation at variable speeds. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motor.

Diagnostic Aids​

A delay or ramp up of approximately 12 seconds may occur before the cooling fan activates or changes speed when being commanded with a scan tool.

Reference Information​

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference


Component Connector End Views

Description and Operation


Cooling Fan Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference


Control Module References for scan tool information

Circuit/System Verification​

1. Ignition ON.
2. Verify that DTC P0480, P0691, or P0692, is not set.
   • If a DTC is set
     Refer to DTC P0480, P0691, or P0692.
   • If no DTC is set.
3. Note: A slight delay may occur before the cooling fan activates.
4. Verify the G10 Cooling Fan Motor activates and increases in speed with each command using a scan tool.
   • The cooling fan does not activate or increase in speed
     Refer to Circuit/System Testing
   • The cooling fan activates and increases in speed
5. All OK.

Circuit/System Testing​

1. Ignition OFF, disconnect the appropriate G10 Cooling Fan Motor harness connector.
2. Ignition ON, verify that a test lamp illuminates between ground circuit terminal 1 and B+.
   • If the test lamp does not illuminate
   • Ignition OFF, test for less than 2 Ω in the ground circuit end to end.
     • If 2 Ω or greater, repair the open/high resistance in the circuit.
     • If less than 2 Ω, repair the open/high resistance in the ground connection.
   • If the test lamp illuminates
3. Verify that a test lamp illuminates between B+ circuit terminal 2 and ground.
   • If the test lamp does not illuminate and the circuit fuse is good
   • Ignition OFF, test for less than 2 Ω in the appropriate B+ circuit end to end.
     • If 2 Ω or greater, repair the open/high resistance in the circuit.
     • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
   • If the test lamp does not illuminate and the circuit fuse is open
   • Ignition OFF, test for infinite resistance between the appropriate B+ circuit terminal and ground.
     • If less than infinite resistance, repair the short to ground in the circuit.
     • If infinite resistance, replace the appropriate G10 Cooling Fan Motor.
   1. If the test lamp illuminates
4. Note: Both G 10 Cooling Fan Motors must be disconnected or incorrect diagnosis may result.
5. Ignition OFF, disconnect the other G 10 Cooling Fan Motor harness connector.
6. Ignition ON, test appropriate G 10 Cooling Fan Motor for 3-4 volts on the control circuit terminal 4.
   • If 3 V or less
   • Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
   • Test for less than 2 Ω between the terminals listed below:
     • G10L Cooling Fan Motor Left - terminal 4
     • G10R Cooling Fan Motor Right - terminal 4
     • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If 3-4 V
7. Test or replace the appropriate G 10 Cooling Fan Motor.

Repair Instructions​

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Fan Blade Replacement for G10 Cooling Fan Motor replacement.
• Control Module References

 

[L8T BURB]

I'm going crazy over this issue. About 4 weeks ago my AC stopped working, I had the system checked for leaks, there were none. I noticed when the AC is on the compressor clutch is engaged but the cooling fans behind the condenser aren’t engaging. The fans behind the condenser were replaced, compressor replaced, HVAC module reprogrammed and $1500 later the AC still blows cold intermittently. When the fans are turning I have cold AC and when they aren’t I get hot air. I've seen videos of the cooling gauge being a issue but my gauge is reading normal. I’m starting to lose faith in the dealer. Any thoughts?

Replace the thermostat assembly and coolant temperature sensor with GM genuine parts and report back. You'll also need about a gallon of Dex-cool.

 

[Sheshe]

Any updates? I’m having a similar issue with my 2015 Tahoe. AC isn’t blowing cold and now my radiator cooling fans aren’t coming on. I replaced the engine coolant temp sensor last month because the cooling fans sounded like they were in overdrive and would not shut off and the temp gauge wasn’t moving. Condenser has been replaced due to leaking and cooling fans were replaced yesterday. They still won’t turn on and still no cold ac