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:

Test the vehicle for UA6 theft deterrent option.

Is the vehicle equipped with UA6 system?

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Go to Step 2

Go to Step 3

Test the vehicle for body control module DTCs.

Refer to Diagnostic System Check - Body Control System in Body Control Systems.

Are any DTCs present?

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Go to the appropriate DTC table in Body Control Systems

Go to Step 3

1. Remove the horn relay.
2. Connect a test lamp between horn relay terminal 86 and ground.

Does the test lamp light?

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Go to Step 4

Go to Step 5

Connect a test lamp between horn relay terminal 30 and ground.

Does the test lamp light?

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Go to Step 6

Go to Step 5

1. Test for a poor connection at the underhood accessory wiring junction block.
2. Test for a poor connection at horn relay terminals 86/30.
3. If the connection is OK, replace the underhood accessory wiring junction block. Relay/Fuse Center Replacement

Is the symptom still present?

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System OK

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

Does the test lamp light?

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Go to Step 10

Go to Step 7

1. Remove the horn switch(es) from the steering wheel.
2. Ensure that the test lamp is still connected between horn relay terminal 86 and terminal 85.
3. Connect a fused jumper (5A) from the ground to the spring loaded terminal leading toward the underhood accessory wiring junction block.

Does the test lamp light?

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Go to Step 9

Go to Step 8

Repair a short to B+ power or an open in CKT 28.

Is the symptom still present?

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System OK

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1. Inspect the ground wire connections for the horn switches in the steering wheel.
2. If all of the connections are OK, replace the horn switches.

•	For Chevrolet refer to Steering Wheel Replacement in Steering Wheel and Column - Tilt.

•	For Pontiac the horn switches are not serviceable. Inspect the horn lead for an open or bad connections, also inspect the inflator module to steering wheel contacts for a bad connection, refer to Inflatable Restraint Steering Wheel Module Replacement in SIR

•	Oldsmobile, refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.

Is the symptom still present?

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System OK

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Momentarily connect a fused jumper (5A) between horn relay terminal 30 and terminal 87.

Do the horns sound?

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Go to Step 11

Go to Step 12

Replace the horn relay, in Underhood Accessory Wiring Junction Block.

Is the symptom still present?

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System OK

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1. Remove the left and right horn connectors.
2. Connect a fused jumper (5A) from the ground to terminal A at the left horn or the right horn.
3. Connect a fused jumper (5A) from B+ power to terminal B at the left horn or the right horn.

Do the horns sound?

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Go to Step 14

Go to Step 13

Replace the inoperative horns. Horn Replacement

Is the symptom still present?

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System OK

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Using a J 39200 , test for continuity to ground in the following circuits:

Do CKT 1250 and CKT 1350 show continuity to ground?

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Go to Step 16

Go to Step 15

Repair CKT 1250 or CKT 1350 for an open to G102 or G101.

Is the repair complete?

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System OK

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Repair an open in CKT 29, between the underhood accessory wiring junction block and the inoperative horn(s).

Is the repair complete?

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System OK

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