GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

SCHEMATIC REFERENCE: Headlights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Does the flash to pass system operate properly?

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Go to Step 3

Go to Step 7

3

Test the low beam relay control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 4

4

Test the high beam relay control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 5

5

Inspect for poor connections at the headlamp switch. 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 17

Go to Step 6

6

Replace the headlamp switch. Refer to Turn Signal and Multifunction Switch Assembly - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

--

Go to Step 17

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7

  1. Turn OFF the Ignition.
  2. Disconnect the high beam headlamp relay.
  3. Connect a test light between the coil side feed circuit of the high beam relay and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 14

8

Connect a test light between the switch side feed circuit of the high beam relay and a good ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 15

9

  1. Turn OFF the Ignition.
  2. Connect a test light between the coil side feed circuit of the high beam relay and the control circuit of the high beam relay.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the high beam relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 10

Go to Step 13

10

  1. Turn OFF the ignition.
  2. Connect a fused jumper between the high beam relay switch side feed circuit and the high beam headlamp supply voltage circuit at the high beam relay connector.
  3. Turn ON the ignition, with the engine OFF.

Did the high beam headlamps illuminate?

--

Go to Step 11

Go to Step 16

11

Inspect for poor connections at the high beam relay. 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 17

Go to Step 12

12

Replace the high beam headlamp relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 17

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13

Repair the open of high resistance in the control circuit of the high beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 17

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14

Repair the open or high resistance in the coil side power feed circuit of the high beam relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

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15

Repair the open or high resistance in the switch side power feed circuit of the high beam relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

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16

Repair the open or high resistance in the high beam headlamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

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17

Operate the system in order to verify the repair

Did you find and complete the condition?

--

System OK

Go to Step 2