GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 Savana 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Blower Motor Always On

Step

Action

Value(s)

Yes

No

1

Was the HVAC Blower Controls System Check performed?

--

Go to Step 2

Go to HVAC Blower Controls System Check

2
  1. Place the heater and A/C controller mode switch in the OFF position.
  2. Place the heater and A/C controller blower motor switch in the HI position.
  3. Disconnect blower motor resistor/relay connector.
  4. Place the ignition switch in the RUN position.
  5. Connect an unpowered test lamp between the blower motor resistor/relay connector, cavity B for CKT 52 (ORN), and ground.

Does the test lamp light?

--

Go to Step 3

Go to Step 4

3
  1. Disconnect the heater and A/C controller C1 connector.
  2. Connect an unpowered test lamp between the heater and A/C controller pin A, and ground.

Does the test lamp light?

--

Go to Step 11

Go to Step 10

4

Connect an unpowered test lamp between the blower motor resistor/relay connector, cavity F for CKT 72 (LT BLU), and ground.

Does the test lamp light?

--

Go to Step 5

Go to Step 6

5
  1. Disconnect the heater and A/C controller C2 connector.
  2. Connect an unpowered test lamp between the heater and A/C controller pin C, and ground.

Does the test lamp light?

--

Go to Step 11

Go to Step 13

6

Connect an unpowered test lamp between the blower motor resistor/relay connector, cavity D for CKT 63 (TAN), and ground.

Does the test lamp light?

--

Go to Step 7

Go to Step 8

7
  1. Disconnect the heater and A/C controller connector C2.
  2. Connect an unpowered test lamp between the heater and A/C controller pin B, and ground.

Does the test lamp light?

--

Go to Step 11

Go to Step 14

8

Connect an unpowered test lamp between the blower motor resistor/relay connector, cavity E for CKT 60 (YEL), and ground.

Does the test lamp light?

--

Go to Step 9

Go to Step 17

9
  1. Disconnect the heater and A/C controller connector C2.
  2. Connect an unpowered test lamp between the heater and A/C controller pin A, and ground.

Does the test lamp light?

--

Go to Step 11

Go to Step 15

10
  1. Disconnect the heater and A/C controller connector C2.
  2. Connect an unpowered test lamp between the heater and A/C controller connector C2, cavity G, and ground.

Does the test lamp light?

--

Go to Step 16

Go to Step 12

11

Replace the heater and A/C controller.

Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

12

Repair the short to voltage in CKT 52 (ORN) between the heater and A/C controller, and the blower motor resistor/relay.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

13

Repair the short to voltage in CKT 72 (LT BLU) between the heater and A/C controller, and the blower motor resistor/relay.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

14

Repair the short to voltage in CKT 63 (TAN) between the heater and A/C controller and the blower motor resistor/relay.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

15

Repair the short to voltage in CKT 60 (YEL) between the heater and A/C controller and the blower motor resistor/relay.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

16

Repair the short to voltage in CKT 119 (WHT) between the heater and A/C controller connectors C1, and C2.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--

17

Replace the blower motor resistor/relay.

Refer to Blower Motor Resistor Replacement .

Is the repair complete?

--

Go to HVAC Blower Controls System Check

--