For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Turn the ignition to RUN.
2. Disconnect the rear defogger relay.
3. Connect a test lamp between terminal 86 and terminal 85 of the relay. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp light?

--

Go to Step 5

Go to Step 2

2 | Connect the test lamp between relay terminal 87 and ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp light? | -- | Go to Step 8 | Go to Step 3
3 |

1. Inspect the relay terminals for proper contacts.
2. Repair the contacts, as necessary. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Did you find and correct the condition?

--

System OK

Go to Step 4

4 | Replace the rear defogger relay. Did you find and correct the condition? | -- | System OK | --
5 |

1. Disconnect the connector of the heater and A/C programmer.
2. Connect a test lamp between terminal 86 and terminal 85 of the relay. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp light?

--

Go to Step 9

Go to Step 6

6 |

1. Inspect the connector of the heater and A/C controller for proper contact.
2. Repair the contacts, as necessary. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Did you find and correct the condition?

--

System OK

Go to Step 7

7 | Replace the heater and A/C programmer. Refer to Programmer Replacement in HVAC. Did you find and correct the condition? | -- | System OK | --
8 |

1. Inspect CKT 293 (PPL) for a short to voltage.
2. Repair the short, as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

System OK

--

9 |

1. Inspect CKT 193 (WHT) for a short to ground.
2. Repair the short, as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

System OK

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