GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Venture Ext. 🢒 Body and Accessories 🢒 Horns 🢒 Horns Always On

Step

Action

Value(s)

Yes

No

Important: Use the J 35616 whenever a diagnostic procedure requires you to test or probe a terminal. Use the J 35616 for the following reasons:

   • In order to prevent damage to the terminal
   • In order to indicate whether the contact tension is sufficient
If the contact tension seems incorrect, refer to Checking Terminal Contact in Troubleshooting Procedures.

1

Inspect the vehicle for UA6 theft deterrent option.

Is the vehicle equipped with UA6 system?

--

Go to Step 2

Go to Step 3

2

Test the vehicle for body control module DTCs. Refer to Diagnostic System Check - Body Control System in Body Control Systems.

Are DTCs present?

--

Go to the appropriate DTC table in Body Control Systems

Go to Step 3

3
  1. Disconnect the horn relay.
  2. Connect a test lamp between horn relay terminal 85 CKT 28 and terminal 86 CKT 740.

Does the test lamp light?

--

Go to Step 4

Go to Step 6

4
  1. Disconnect the body control module (BCM) connector C2.
  2. Connect a test lamp in the same location.

Does the test lamp light?

--

Go to Step 5

Go to Step 7

5
  1. Inspect for a short to ground in CKT 28 between the horn switch(es) and the underhood accessory wiring junction block.
  2. Inspect for a short to ground in CKT 28 between the BCM and the underhood accessory wiring junction block.

Is the repair complete?

--

System OK

--

6
  1. Test for a short to B+ in CKT 29.
  2. If CKT 29 is OK, replace the horn relay in Underhood Accessory Wiring Junction Block.

Is the repair complete?

--

System OK

--

7

Replace the BCM. Refer to Body Control Module Replacement .

Is the repair complete?

--

System OK

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