GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Horns System Check?

--

Go to Step 2

Go to Horns System Check

2

  1. Disconnect the horn relay.
  2. Connect the test lamp between the relay terminal 85 and ground.
  3. Connect the test lamp between the relay terminal 30 and ground.

Does the test lamp light at both terminals?

--

Go to Step 4

Go to Step 3

3

Repair an open in CKT 1142 (RED). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

4

Connect a fused jumper between the relay terminal 87 and terminal 30.

Do the horns sound?

--

Go to Step 6

Go to Step 5

5

  1. Disconnect the left horn and the right horn.
  2. Connect the fused jumper between relay terminal 87 and terminal 30.
  3. Connect the test lamp between horn connector terminal B and ground.

Does the test lamp light?

--

Go to Step 8

Go to Step 7

6

  1. Connect the test lamp between relay terminal 86 and terminal 85.
  2. Press the horn switch.

Does the test lamp light?

--

Go to Step 10

Go to Step 9

7

Repair an open in CKT 29 (DRK GRN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

8

    • Connect the test lamp between horn connector terminal B and terminal A.
    • Repeat this procedure for each horn.

Does the test lamp light?

--

Go to Step 12

Go to Step 11

9

Test for an open in CKT 28 (BLK).

Was an open found?

--

Go to Step 13

Go to Step 14

10

Replace the horn relay. Refer to Horn Relay Replacement .

Is the repair complete?

--

Go to Horns System Check

--

11

Repair the open in CKT 1350 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

12

Replace the horns. Refer to Wiring Repairs . in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

13

Repair an open in CKT 28 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

--

14

Replace the horn switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Horns System Check

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