For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Exchange the blower motor relay with a known good relay from the underhood junction block. Does the blower motor operate? | -- | Go to Step 2 | Go to Step 3
2 | Replace the faulty relay. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
3 | Backprobe the underhood junction block connector C3 using a fused jumper between terminal B9 and B+. Does the blower motor operate? | -- | Go to Step 9 | Go to Step 4
4 |

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 5

Go to Step 6

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

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 13

Go to Step 10

10 |

1. Use the J 39200 DMM in order to backprobe the right side IP 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 11

Go to Step 12

11 | Repair the open in CKT 641 between the right IP 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 | --
12 | Replace the right IP junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
13 |

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 15

Go to Step 14

14 | Replace the heater A/C control assembly. Refer to Control Assembly Replacement . Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
15 |

1. Disconnect the blower resistor assembly connector.
2. Disconnect the underhood 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 16

Go to Step 18

16 | Backprobe the underhood junction block connector C3 using a fused jumper between terminal C10 and B+. Does the blower motor operate? | -- | Go to Step 17 | Go to Step 19
17 | Replace the blower resistor assembly. Refer to Blower Motor Resistor Replacement Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --
18 | 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 | --
19 | Replace the underhood junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems. Is the repair complete? | -- | Go to HVAC Blower Controls System Check | --