For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.
1 | Did you perform the Horns System Check? | -- | Go to Step 2 | Go to Horns System Check
2 |

1. Use a test lamp in order to backprobe the underhood wiring harness junction block between terminal C12 of connector C2 and ground.
2. Press and hold the horn switch.

Does the test lamp light?

--

Go to Step 10

Go to Step 3

3 |

1. Exchange the horn relay with a known good relay from the underhood wiring harness junction block.
2. Press the horn switch.

Does the horn sound?

--

Go to Step 4

Go to Step 5

4 | Replace the faulty relay. Is the repair complete? | -- | Go to Horns System Check | --
5 | Use a fused jumper in order to backprobe the underhood wiring harness junction block between terminal C12 of connector C3 and ground. Does the horn sound? | -- | Go to Step 7 | Go to Step 6
6 | Replace the underhood wiring harness junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems. Is the repair complete? | -- | Go to Horns System Check | --
7 | Use the J 39200 Digital Multimeter (DMM) in order to backprobe the turn/headlamp switch assembly between terminal A of connector C2 and ground. Does the voltage measure to the specified value? | B+ | Go to Step 9 | Go to Step 8
8 | Repair the open in CKT 28 between the underhood wiring harness junction block and the turn/headlamp switch assembly. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Horns System Check | --
9 | Repair the open in the horn switch. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement in SIR. Is the repair complete? | -- | Go to Horns System Check | --
10 |

1. Disconnect the horn assembly connector.
2. Connect a test lamp between terminal B or the horn assembly connector and ground.
3. Press and hold the horn switch.

Does the test lamp light?

--

Go to Step 11

Go to Step 12

11 |

1. Disconnect the horn assembly connector.
2. Connect a test lamp between terminal A and terminal B of the horn assembly connector.
3. Press and hold the horn switch.

Does the test lamp light?

--

Go to Step 13

Go to Step 14

12 | Repair the open in CKT 29 between the underhood wiring harness junction block and the horn assembly. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Horns System Check | --
13 | Replace the horn assembly. Refer to Horn Replacement Is the repair complete? | -- | Go to Horns System Check | --
14 | Repair the open in CKT 1350 between the horn assembly and ground splice pack G101. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Horns System Check | --