GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 LSS 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Blower Motor Inoperative at Any Speed

Step

Action

Value(s)

Yes

No

1
  1. Disconnect the blower motor connector.
  2. Turn the ignition to the RUN position.
  3. Move to DEF mode.
  4. Turn the blower speed to HIGH.
  5. Measure the voltage between blower motor connector terminal A and ground.

Does the voltage equal the specified value?

12 V

Go to Step  2

Go to Step  7

2

Measure the voltage between blower motor connector terminal A and terminal B.

Refer to Measuring Voltage in Wiring Systems.

Does the voltage equal the specified value?

12 V

Go to Step  6

Go to Step  3

3

Inspect CKT 1550 for an open.

Did you find an open?

--

Go to Step  4

Go to Step  5

4

Repair the open in CKT 1550.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

System OK

--

5

Inspect ground G105.

Is the ground clean and tight?

--

System OK

--

6
  1. Inspect the blower motor connector terminals for proper contact.

    2. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

  2. If the terminal contact is OK, replace the blower motor. Refer to Blower Motor and Fan Replacement .

Is the repair complete?

--

System OK

--

7

Inspect CKT 65 for an open or short to ground.

Did you find the open or short to ground?

--

Go to Step  8

Go to Step  9

8

Repair the open or short to ground in CKT 65.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

System OK

--

9
  1. Disconnect the blower control module connector C1 and connector C2.
  2. Measure the voltage between blower control module connector C1 terminal B and ground.

    3. Refer to Measuring Voltage in Wiring Systems.

Does the voltage equal the specified value?

12 V

Go to Step  10

Go to Step  15

10

Measure the voltage between blower control module connector C1 terminal B and connector C2 terminal C.

Refer to Measuring Voltage in Wiring Systems.

Does the voltage equal the specified value?

12 V

Go to Step  11

Go to Step  5

11

Measure the voltage between blower control module connector C2 terminal B and ground.

Refer to Measuring Voltage in Wiring Systems.

Does the voltage equal the specified value?

6 V

Go to Step  14

Go to Step  12

12

Inspect CKT 754 (GRY/BLK) for an open or short to ground.

Did you find the open or short to ground?

--

Go to Step  13

Go to Step  14

13

Repair the open or short to ground in CKT 754 (GRY/BLK).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step  14

--

14
  1. Inspect the terminal contact at blower control module connector C1 and connector C2.

    2. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

  2. If the terminal contact is OK, replace the blower control module. Refer to Blower Motor Control Module Replacement .

Is the repair complete?

--

System OK

--

15

Inspect CKT 442 for an open or short to ground.

Did you find the open or short to ground?

--

Go to Step  16

Go to Step  17

16

Repair the open or short to ground in CKT 442.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

System OK

--

17
  1. Inspect the terminal contact at the HVAC programmer.
  2. If the terminal contact is OK, replace the HVAC programmer. Refer to Programmer Replacement .

Is the repair complete?

--

System OK

--