GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 CTS 🢒 Body 🢒 Lighting Systems 🢒 Headlamps Inoperative - High Beams

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the relay operates. Cycle between low and high positions. Repeat the cycles as necessary.

    2.

  2. This step tests for supply voltage at the coil side of the relay.

    3.

  3. This step verifies that the headlamp switch is providing ground to the relay.

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the headlamp switch.
  3. Move the headlamp dimmer switch between the high beam and low beam positions.
  4. Turn OFF the headlamp switch.
  5. Turn OFF the ignition.

Did the high beam headlamps operate properly?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the low beam headlamps operate properly?

Go to Step 4

Go to Headlamps Inoperative - Low Beams

4

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the headlamps.
  3. Cycle the headlamp dimmer switch between low and high beams.

Does the headlamp high beam relay turn ON and OFF with each cycle?

Go to Step 7

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the headlamp high beam relay. Refer to Relay Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the coil side supply voltage circuit of the headlamp high beam relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 18

6

  1. Connect a test lamp between the headlamp high beam relay control circuit of the headlamp high beam relay and the coil side supply voltage circuit of the headlamp high beam relay.
  2. Cycle the headlamp dimmer switch between low beams and high beams.

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

Go to Step 13

Go to Step 10

7
  1. Turn OFF the ignition.
  2. Disconnect the headlamp high beam relay. Refer to Relay Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the switch side supply voltage circuit of the headlamp high beam relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 17

8
  1. Turn OFF the ignition.
  2. Connect a 20-amp fused jumper between the headlamp high beam relay switch side supply voltage circuit and the headlamp high beam supply voltage circuit.
  3. Turn ON the ignition, with the engine OFF.

Did both of the high beam headlamps illuminate?

Go to Step 13

Go to Step 9

9
  1. Disconnect the inoperative high beam headlamp bulb.
  2. Connect a test lamp between the inoperative headlamp high beam supply voltage circuit and inoperative headlamp high beam ground circuit.

Does the test lamp illuminate?

Go to Step 15

Go to Step 11

10

Test the headlamp high beam relay control circuit for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 12

11

Test the headlamp high beam supply voltage circuit for a high resistance or open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 16

12

Test the headlamp low beam relay control circuit of the headlamp dimmer switch for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 14

13

Inspect for poor connections at the headlamp high beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 19

14

Inspect for poor connections at the harness connector of the multifunction, turn signal switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 20

15

Inspect for poor connections at the inoperative high beam headlamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 22

Go to Step 21

16

Repair the open or high resistance in the ground circuit of the inoperative high beam headlamp bulb. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 22

--

17

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

Did you complete the repair?

Go to Step 22

--

18

Repair the headlamp high beam coil side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 22

--

19

Replace the headlamp high beam relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 22

--

20

Replace the multifunction, turn signal switch. Refer to Turn Signal Multifunction Switch Replacement .

Did you complete the replacement?

Go to Step 22

--

21

Replace the inoperative high beam headlamp bulb. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement .

Did you complete the replacement?

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2