Auxiliary Blower Motor Always On. GMC Truck Savana

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2005 🢒 Savana - AWD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Auxiliary Blower Motor Always On

Auxiliary Blower Motor Always On Passenger Van w/Aux

Test Description

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

The auxiliary blower motor switch control circuit is the circuit that enables the rear auxiliary HVAC control assembly when the front auxiliary blower motor switch is placed in the rear control position.

Step	Action	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary blower motor is ON while the auxiliary blower motor switches is in the OFF position.
1	Did you review the HVAC operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - HVAC Systems - Manual
2	Turn ON the ignition, with the engine OFF. Place the rear auxiliary blower motor switch in the maximum speed position. Place the front auxiliary blower motor switch in the OFF position. Is the auxiliary blower motor OFF?	Go to Step 3	Go to Step 5
3	Place the front auxiliary blower motor switch in the rear control position. Place the rear auxiliary blower motor switch in the OFF position. Is the auxiliary blower motor OFF?	Go to Testing for Intermittent Conditions and Poor Connections	Go to Step 20
4	Turn off the ignition. Place the rear auxiliary blower motor switch in any speed position. Does the rear auxiliary blower motor operate?	Go to Step 25	Go to Step 5
5	Turn OFF the ignition. Disconnect the front auxiliary HVAC control assembly. Turn ON the ignition, with the engine OFF. Does the auxiliary blower motor continue to operate?	Go to Step 6	Go to Step 19
6	Place the rear auxiliary blower motor switch in the OFF position. Does the auxiliary blower motor continue to operate?	Go to Step 7	Go to Step 14
7	Turn OFF the ignition. Disconnect the rear auxiliary HVAC control assembly. Turn ON the ignition, with the engine OFF. Does the auxiliary blower motor continue to operate?	Go to Step 8	Go to Step 20
8	Probe each blower motor control circuit of the rear auxiliary HVAC control assembly with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate when connected to any auxiliary blower motor speed control circuit?	Go to Step 22	Go to Step 9
9	Turn OFF the ignition. Disconnect the auxiliary blower motor resistor assembly. Turn ON the ignition, with the engine OFF. Does the auxiliary blower motor continue to operate?	Go to Step 10	Go to Step 11
10	Test the auxiliary blower motor supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 18
11	Probe the auxiliary blower motor low speed control circuit of the auxiliary blower motor resistor assembly with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 12	Go to Step 13
12	Test the auxiliary blower motor low speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary low speed blower motor relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 16
13	Test the auxiliary blower motor medium speed control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 17
14	Test the auxiliary blower motor switch control circuit between the rear auxiliary HVAC control assembly and the auxiliary HVAC control processor for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 15
15	Test the auxiliary blower motor switch control circuit between the front auxiliary HVAC control assembly and the auxiliary HVAC control processor for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 21
16	Inspect for poor connections at the harness connector of the auxiliary low speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 25
17	Inspect for poor connections at the harness connector of the auxiliary medium speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 26
18	Inspect for poor connections at the harness connector of the auxiliary high speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 27
19	Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 28
20	Inspect for poor connections at the harness connector of the rear auxiliary HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 29
21	Inspect for poor connections at the harness connector of the auxiliary HVAC control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 31	Go to Step 30
22	Repair the short to ground in the appropriate blower motor control circuit of the rear auxiliary HVAC control assembly. Refer to Wiring Repairs . Did you complete the repair?	Go to Step 31	--
23	Test the ignition 3 voltage circuit for a short to power. Did you find and correct the condition?	Go to Step 31	Go to Step 24
24	Test the appropriate auxiliary blower motor control circuit for a short to power. Did you find and correct the condition?	Go to Step 31	--
25	Replace the auxiliary low speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 31	--
26	Replace the auxiliary medium speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 31	--
27	Replace the auxiliary high speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 31	--
28	Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front . Did you complete the replacement?	Go to Step 31	--
29	Replace the rear auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Rear . Did you complete the replacement?	Go to Step 31	--
30	Replace the auxiliary HVAC control processor. Refer to Auxiliary HVAC Control Processor Replacement . Did you complete the replacement?	Go to Step 31	--
31	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2

Auxiliary Blower Motor Always On Aux Heat Only or Cargo Van w/Aux

Step	Action	Yes	No
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary blower motor is ON while the auxiliary blower motor switch in the OFF position.
1	Did you review the HVAC operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - HVAC Systems - Manual
2	Turn ON the ignition, with the engine OFF. Place the auxiliary blower motor switch in the OFF position. Is the auxiliary blower motor OFF?	Go to Testing for Intermittent Conditions and Poor Connections	Go to Step 3
3	Turn OFF the ignition. Disconnect the auxiliary blower motor switch, auxiliary heat only or the front auxiliary HVAC control assembly, with auxiliary heat and A/C. Turn ON the ignition, with the engine OFF. Does the auxiliary blower motor continue to operate?	Go to Step 4	Go to Step 13
4	Probe each auxiliary blower motor control circuit of the auxiliary blower motor switch, auxiliary heat only, or the front auxiliary HVAC control assembly, with auxiliary heat and A/C, with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate when connected to any auxiliary blower motor speed control circuit?	Go to Step 14	Go to Step 5
5	Turn OFF the ignition. Disconnect the auxiliary blower motor resistor assembly. Turn ON the ignition, with the engine OFF. Does the auxiliary blower motor continue to operate?	Go to Step 6	Go to Step 7
6	Test the auxiliary blower motor supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 12
7	Probe the auxiliary blower motor low speed control circuit of the auxiliary blower motor resistor assembly with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 8	Go to Step 9
8	Test the auxiliary blower motor low speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary low speed blower motor relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 10
9	Test the auxiliary blower motor medium speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary medium speed blower motor relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 11
10	Inspect for poor connections at the harness connector of the auxiliary low speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 15
11	Inspect for poor connections at the harness connector of the auxiliary medium speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 16
12	Inspect for poor connections at the harness connector of the auxiliary high speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 17
13	Inspect for poor connections at the harness connector of the auxiliary blower motor switch, auxiliary heat only, or front auxiliary HVAC control assembly, with auxiliary heat and A/C. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 19	Go to Step 18
14	Repair the short to ground in the appropriate auxiliary blower motor speed control circuit of the auxiliary blower motor switch, auxiliary heat only, or the front auxiliary HVAC control assembly with auxiliary heat and A/C. Refer to Wiring Repairs . Did you complete the repair?	Go to Step 19	--
15	Replace the auxiliary low speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 19	--
16	Replace the auxiliary medium speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 19	--
17	Replace the auxiliary high speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement . Did you complete the replacement?	Go to Step 19	--
18	Replace the auxiliary blower motor switch, auxiliary heat only, or the front auxiliary HVAC control assembly, cargo van with auxiliary heat and A/C. Refer to Auxiliary Blower Motor Switch Replacement or Auxiliary Heater and Air Conditioning Control Replacement - Front . Did you complete the repair?	Go to Step 19	--
19	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2