Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
A short to ground in the battery positive voltage circuit of the blower motor relay will cause the HVAC BLO fuse to open.
-
This step tests for a high resistance or an open in the coil side feed circuit of the blower motor relay.
-
This step tests for a high resistance or an open in the battery positive voltage circuit of the blower motor relay.
-
This step tests the suspect speed control circuit for a high resistance or an open.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you review the Control Assembly Description and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms |
2 |
Does the blower motor operate in all speeds? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 | Does the blower motor operate in high speed (5) ? | -- | Go to Step 7 | Go to Step 4 |
Inspect the HVAC BLO fuse. Is the fuse open? | -- | Go to Step 12 | Go to Step 5 | |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 8 | |
Probe the switch side feed circuit of the blower motor relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 13 | |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 9 | |
8 | Test the high for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 10 |
9 | Test the suspect speed control circuit (1, 2, 3, or 4) for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 |
10 | Inspect for poor connections at the harness connector of the blower motor resistor. 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 16 | Go to Step 14 |
11 | Inspect for poor connections at the harness connector of the heater-A/C control module. 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 16 | Go to Step 15 |
12 | Repair the short to ground in the switch side feed circuit of the blower motor relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | -- |
13 | Repair the open in the switch side feed circuit of the blower motor relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | -- |
14 | Replace the blower motor resistor. Refer to Blower Motor Resistor Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
15 | Replace the heater - A/C control module. Refer to Control Assembly Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
16 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
