GM Service Manual Online
For 1990-2009 cars only

Horns On At All Times

Step

Action

Value(s)

Yes

No

DEFINITION: Horns on at all time.

1

Was the Horns Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Horns

2

  1. Turn ignition OFF.
  2. Unplug horns.
  3. Connect a test lamp between the horn terminal B, CKT 29 (DK GRN) and ground.
  4. Remove the horn relay.

Does the test lamp light?

--

Go to Step 3

Go to Step 7

3

Disconnect the Underhood Junction Block connector C1.

Does the test lamp light?

--

Go to Step 5

Go to Step 4

4

Replace the Underhood Junction Block

Is the repair complete?

--

Go to Diagnostic System Check - Horns

--

5

Repair short to voltage in CKT 29 (DK GRN).

Is the repair complete?

--

Go to Diagnostic System Check - Horns

--

6

Connect a test lamp between the Underhood Junction Block  C2 terminal  D10 and B+ voltage.

Does the test lamp light?

--

Go to Step 8

Go to Step 3

7

Replace the horn relay.

Is the repair complete?

--

Go to Diagnostic System Check - Horns

Go to Step 4

8

Disconnect the Underhood Junction Block connector C2.

Does the test lamp light?

--

Go to Step 9

Go to Step 4

9

  1. Connect a test lamp between the Underhood Junction Block connector C2, terminal  D1 and battery (B+).
  2. Disconnect the C202 connector.

Does the test lamp light?

--

Go to Step 11

Go to Step 10

10

Repair short to ground in CKT 28.

Is the repair complete?

--

Go to Diagnostic System Check - Horns

--

11

Disconnect the Dash Integration Module (DIM).

Does the test lamp light?

--

Go to Step 13

Go to Step 12

12

Replace the Dash Integration Module (DIM), refer to DIM replacement.

Is the repair complete?

--

Go to Diagnostic System Check - Horns

--

13

Repair short to ground in CKT 28 (BLK).

Is the repair complete?

--

Go to Diagnostic System Check - Horns

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