Auxiliary Blower Motor Always On. Chevrolet Express 2001

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2001 🢒 Express 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Auxiliary Blower Motor Always On

Auxiliary Blower Motor Always On Passenger Van With Auxiliary A/C

Test Description

The number(s) below refer to the step number(s) 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 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 4
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 in Wiring Systems	Go to Step 19
4	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 5	Go to Step 18
5	Place the rear auxiliary blower motor switch in the OFF position. Does the auxiliary blower motor continue to operate?	Go to Step 6	Go to Step 13
6	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 7	Go to Step 19
7	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 21	Go to Step 8
8	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 9	Go to Step 10
9	Test the auxiliary blower motor supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 17
10	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 11	Go to Step 12
11	Test 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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 15
12	Test auxiliary blower motor medium speed control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 16
13	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 14
14	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 20
15	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 22
16	Inspect for poor connections at the harness connector of the auxiliary med speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 23
17	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 24
18	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 25
19	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 26
20	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 in Wiring Systems. Did you find and correct the condition?	Go to Step 28	Go to Step 27
21	Repair the short to ground in the appropriate blower motor control circuit of the rear auxiliary HVAC control assembly. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 28	--
22	Replace the auxiliary low speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement?	Go to Step 28	--
23	Replace the auxiliary med speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement?	Go to Step 28	--
24	Replace the auxiliary high speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement?	Go to Step 28	--
25	Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front . Did you complete the repair?	Go to Step 28	--
26	Replace the rear auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Rear . Did you complete the repair?	Go to Step 28	--
27	Replace the auxiliary HVAC control processor. Refer to Auxiliary HVAC Control Processor Replacement . Did you complete the repair?	Go to Step 28	--
28	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 A/C

Step	Action	Yes	No
Schematic Reference: HVAC Schematics 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 in Wiring Systems	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 (w/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 speed control circuit of the auxiliary blower motor switch (auxiliary heat only) or the front auxiliary HVAC control assembly (w/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 in Wiring Systems. 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 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 in Wiring Systems. Did you find and correct the condition?	Go to Step 19	Go to Step 10
9	Test auxiliary blower motor medium speed control circuit between the auxiliary blower motor resistor assembly and the auxiliary med speed blower motor relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 in Wiring Systems. 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 med speed blower motor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. 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 in Wiring Systems. 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 (w/auxiliary heat and A/C). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. 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 (w/auxiliary heat and A/C). Refer to Wiring Repairs in Wiring Systems. 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 in Heating, Ventilation and Air Conditioning. Did you complete the replacement?	Go to Step 19	--
16	Replace the auxiliary med speed blower motor relay. Refer to Auxiliary Blower Motor Relay Replacement in Heating, Ventilation and Air Conditioning. 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 in Heating, Ventilation and Air Conditioning. 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 w/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