Blower Motor Inoperative. GMC Truck GMC Sierra Denali 2006

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2006 🢒 GMC Sierra Denali 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Blower Motor Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step tests the output from the blower motor switch. Loss of blower motor switch output would indicate a malfunctioning switch or a circuit malfunction in the supply voltage to the switch.

There are two ignition 3 voltage circuits at the HVAC control module. Test the circuit that provides the supply voltage to the blower motor switch.

Step	Action	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor is inoperative in all speed positions.
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	Turn ON the ignition, with the engine OFF. Place the blower motor switch in each speed position. Does the blower motor operate in any of the speed positions?	Go to Blower Motor Malfunction	Go to Step 3
3	Turn OFF the ignition. Disconnect the blower motor. Turn ON the ignition, with the engine OFF. Connect a test lamp between the blower motor supply voltage circuit and a good ground. Place the blower motor switch in the minimum speed position. Does the test lamp illuminate?	Go to Step 4	Go to Step 6
4	Connect a test lamp between the blower motor supply voltage circuit and the blower motor ground circuit. Does the test lamp illuminate?	Go to Step 8	Go to Step 5
5	Test the ground circuit of the blower motor resistor assembly for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 16	Go to Step 9
6	Turn OFF the ignition. Disconnect the blower motor resistor assembly connector. Turn ON the ignition, with the engine OFF. Place the blower motor switch in the minimum speed position. Connect a test lamp between the low blower motor control circuit of the blower motor resistor assembly and a good ground. Does the test lamp illuminate?	Go to Step 9	Go to Step 7
7	Turn OFF the ignition. Disconnect the HVAC control module. Turn ON the ignition, with the engine OFF. Connect a test lamp between the ignition 3 voltage circuit of the blower motor switch and a good ground. Does the test lamp illuminate?	Go to Step 11	Go to Step 12
8	Inspect for poor connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 16	Go to Step 13
9	Visually inspect the blower motor harness of the blower motor resistor assembly for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 16	Go to Step 10
10	Inspect for poor connections at the harness connector of the blower motor resistor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 16	Go to Step 14
11	Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 16	Go to Step 15
12	Repair the ignition 3 voltage circuit of the blower motor switch. Refer to Wiring Repairs . Did you complete the repair?	Go to Step 16	--
13	Replace the blower motor. Refer to Blower Motor Replacement . Did you complete the replacement?	Go to Step 16	--
14	Replace the blower motor resistor. Refer to Blower Motor Resistor Replacement . Did you complete the replacement?	Go to Step 16	--
15	Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?	Go to Step 16	--
16	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3