GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Horns System Check performed?

--

Go to Step 2

Go to Horns System Check

2

Remove the horn relay K63 from the relay box.

Do the horns still sound?

--

Go to Step 3

Go to Step 4

3

Locate and repair a short to ground in one of the following circuits:

    • XM30
    • XM60
    • XM65
    • XM70

Is the repair complete?

--

Go to Step 9

--

4

Using a DMM, measure the resistance from terminal 6 of the horn relay K63 and a known good ground.

Is the measured resistance less than the specified value?

5ohms

Go to Step 5

Go to Step 7

5

  1. Disconnect the horn switch.
  2. Using a DMM, measure the resistance from terminal 6 of the horn relay K63 and a known good ground.

Is the measured resistance less than the specified value?

5ohms

Go to Step  6

Go to Step 8

6

  1. Locate a short to ground in CKT XM1 and/or CKT XM899.
  2. Replace the BCM if CKT XM899 and/or CKT XM1 is OK. Refer to Body Control Module Replacement in Body Control System.

Is the repair complete?

--

Go to Step 9

--

7

Replace the horn relay K63. Refer to Horn Relay Replacement .

Is the replacement complete?

--

Go to Step 9

Go to Step 5

8

Replace the horn switch. Refer to Horn Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Is the replacement complete?

--

Go to Step 9

--

9

  1. Connect all of the connectors and reinstall the components that were disconnected.
  2. Verify that both horns operate properly.

Do both of the horns operate properly?

--

System OK

Go to Step 1