GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 DeVille 🢒 Body and Accessories 🢒 Horns 🢒 Horns Always On

Step

Action

Yes

No

SCHEMATIC REFERENCE: Horn Schematics

1

Did you perform the Horns Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Horns

2
  1. Turn ON the ignition, with the engine OFF.
  2. Remove the horn relay.

Do the horns sound?

Go to Step 8

Go to Step 3

3

Connect a test lamp between the horn relay control circuit and battery positive voltage.

Does the test lamp illuminate?

Go to Step 4

Go to Step 9

4

Caution: This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions:

   • Air bag deployment
   • Personal injury
   • Unnecessary SIR system repairs
In order to avoid the above conditions, observe the following guidelines:
   • Refer to SIR Component Views in order to determine if you are performing service on or near the SIR components or the SIR wiring.
   • If you are performing service on or near the SIR components or the SIR wiring, disable the SIR system. Refer to Disabling the SIR System.

Important: The horn switch is part of the steering wheel module inflatable restraint.

  1. Disable the SIR system. Refer to Disabling the SIR System in SIR.
  2. Disconnect the horn switch. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Step 10

5

Disconnect the Dash Integration Module (DIM).

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

6

Inspect for poor connections at the harness connector of the Dash Integration Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

7

Repair a short to ground in the horn relay control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

--

8

Repair a short to voltage in the supply voltage circuit of the horns. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

--

9

Replace the horn relay. Refer to Horn Relay Replacement .

Did you complete the replacement?

Go to Step 12

--

10

Caution: This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions:

   • Air bag deployment
   • Personal injury
   • Unnecessary SIR system repairs
In order to avoid the above conditions, observe the following guidelines:
   • Refer to SIR Component Views in order to determine if you are performing service on or near the SIR components or the SIR wiring.
   • If you are performing service on or near the SIR components or the SIR wiring, disable the SIR system. Refer to Disabling the SIR System.

Important: The horn switch is part of the steering wheel module inflatable restraint and is not serviceable separately.

Replace the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.

Did you complete the replacement?

Go to Step 12

--

11

Replace the Dash Integration Module (DIM). Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2