GM Service Manual Online
For 1990-2009 cars only

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

  1. Remove the horn relay.
  2. Backprobe the convenience center connector C1 with a test lamp between terminal R and the ground.

Does the test lamp light?

--

Go to Step 2

Go to Step 3

2

  1. Backprobe the convenience center connector C1 with a test lamp between terminal R and terminal S.
  2. Press and hold the horn switch.

Does the test lamp light?

--

Go to Step 4

Go to Step 5

3

Repair the open in CKT 40 between the fuse block and the convenience center. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

4

Backprobe the convenience center connector C1 with a fused jumper between terminal R and terminal T.

Does the horn sound?

--

Go to Step 6

Go to Step 7

5

  1. Reconnect the horn relay.
  2. Disconnect the turn/hazard headlamp switch assembly connector C2.
  3. Connect a fused jumper between terminal H of the turn/hazard headlamp switch assembly harness connector C2 and the ground.

Does the horn sound?

--

Go to Step 8

Go to Step 9

6

Replace the horn relay.

Is the repair complete?

--

Go to Horns System Check

--

7

  1. Reinstall the horn relay.
  2. Disconnect the horn connector.
  3. Connect a test lamp between terminal B of the horn harness connector and the ground.
  4. Press and hold the horn switch.

Does the test lamp light?

--

Go to Step 10

Go to Step 11

8

Replace the turn/hazard headlamp switch assembly.

Is the repair complete?

--

Go to Horns System Check

--

9

Repair the open in CKT 28, between the convenience center and the turn/hazard headlamp switch assembly. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

10

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

Does the test lamp light?

--

Go to Step 12

Go to Step 13

11

Repair the open in CKT 29 between the convenience center and the horn. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

12

Replace the horn. Refer to Horn Replacement in Horns.

Is the repair complete?

Go to Horns System Check

13

Repair the open in CKT 150 between the horn and ground G102. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Horns System Check