For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: A short to ground will cause an open fuse. Before performing this diagnostic procedure, inspect the fuses for an open.
1 | Did you perform the HVAC Blower Controls System Check? | -- | Go to Step 2 | Go to HVAC Blower Controls System Check
2 | Exchange the blower motor relay with a known good relay from the underhood wiring harness junction block. Does the blower motor operate? | -- | Go to Step 3 | Go to Step 4
3 | Replace the faulty relay. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
4 | Backprobe the underhood wiring harness junction block connector C3 using a fused jumper between terminal B9 and B+. Does the blower motor operate? | -- | Go to Step 10 | Go to Step 5
5 |

1. Turn the ignition switch to the ON position.
2. Turn the blower switch to M3.
3. Disconnect the blower motor connector.
4. Connect a test lamp between terminal B of the blower motor connector and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

6 | Connect a test lamp between terminal A and terminal B of the blower motor connector. Does the test lamp light? | -- | Go to Step 8 | Go to Step 9
7 | Repair the open in CKT 65 between the underhood wiring harness junction block and the blower motor. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
8 | Replace the blower motor. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
9 | Repair the open in CKT 250 between the blower motor and ground splice pack G203. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
10 |

1. Turn the ignition switch to the ON position.
2. Use the J 39200 Digital Multimeter (DMM) in order to backprobe the heater A/C control assembly connector C1.
3. Measure the voltage between terminal B and ground.

Does the voltage measured equal the specified value?

B+

Go to Step 14

Go to Step 11

11 |

1. Use the J 39200 DMM in order to backprobe the right side IP wiring harness junction block connector C1.
2. Measure the voltage between terminal A5 and ground.

Does the voltage measured equal the specified value?

B+

Go to Step 12

Go to Step 13

12 | Repair the open in CKT 641 between the right side IP wiring harness junction block and the heater A/C control assembly. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
13 | Replace the right side IP wiring harness junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
14 |

1. Turn the blower switch to M3.
2. Use the J 39200 DMM in order to backprobe the heater A/C control assembly connector C1.
3. Measure the voltage between terminal E and ground.

Does the voltage measured equal the specified value?

B+

Go to Step 16

Go to Step 15

15 | Replace the heater A/C control assembly. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
16 |

1. Disconnect the blower resistor assembly connector.
2. Disconnect the underhood wiring harness junction block connector C3.
3. Use a J 39200 DMM in order to measure the resistance between the blower resistor connector terminal E and the junction block connector C3 terminal C10.

Is the resistance within the specified range?

0-2ohms

Go to Step 17

Go to Step 19

17 | Backprobe the underhood wiring harness junction block connector C3 using a fused jumper between terminal C10 and B+. Does the blower motor operate? | -- | Go to Step 18 | Go to Step 20
18 | Replace the blower resistor assembly. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
19 | Repair the open in CKT 101 between the blower resistor terminal E and the underhood wire harness junction block connector C3 terminal C10. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
20 | Replace the underhood wiring harness junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --