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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Montana Ext. 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlamps Inoperative - One Lamp

Headlamps Inoperative - One Lamp Domestic

Step

Action

Value(s)

Yes

No

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
    • For the low beam, verify that only one low beam headlamp is inop.
    • For the high beam, verify that only one high beam headlamp is inop.

Are both low beam or both high beam headlamps inop?

--

Go to Headlamps Inoperative - Low Beams or Headlamps Inoperative - High Beams

Go to Step 3

3
  1. Disconnect the inoperative headlamp connector.
  2. Turn the headlamp switch to the HEAD position.
  3. Complete the following steps if the low beam is inoperative:
    4. • Turn the headlamp dimmer switch to the LOW position.
    • Use a test lamp in order to backprobe from the inoperative headlamp connector terminal B to ground.
  4. Complete the following steps if the high beam is inoperative:
    5. • Turn the headlamp dimmer switch to the HIGH position.
    • Use a test lamp in order to backprobe from the inoperative headlamp connector terminal C to ground.

Did the test lamp light?

--

Go to Step 4

Go to Step 5

4
    • If the low beam is inoperative, use a test lamp in order to frontprobe the inoperative headlamp connector B to headlamp connector A.
    • If the high beam is inoperative, use a test lamp in order to frontprobe the inoperative headlamp connector C to headlamp connector A.

Did the test lamp light?

--

Go to Step 7

Go to Step 8

5
  1. Complete the following steps for the left headlamp:
    2. • For the low beam, use a test lamp in order to backprobe between the underhood accessory junction block harness C3 terminal B8 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood accessory junction block harness C3 terminal B4 and ground.
  2. Complete the following steps for the right headlamp:
    3. • For the low beam, use a test lamp in order to backprobe between the underhood accessory junction block harness C3 terminal A8 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood accessory junction block harness C3 terminal A4 and ground.

Did the test lamp light?

--

Go to Step 6

Go to Step 9

6
    • For the low beam, repair an open in CKT 12 between the underhood accessory junction block harness connector and the inoperative headlamp connector terminal B.
    • For the high beam, repair an open in CKT 11 between the underhood accessory junction block harness connector and the inoperative headlamp connector terminal C.

Has the repair been completed?

--

Go to Step 10

--

7

Replace the headlamp. Refer to Headlamp Assembly or Headlamp Bulb Replacement .

Has the repair been completed?

--

Go to Step 10

--

8
    • For the left headlamp, repair an open in CKT 1350 between the headlamp connector terminal A and G101.
    • For the right headlamp, repair an open in CKT 1250 between the headlamp connector terminal A and G102.

Has the repair been completed?

--

Go to Step 10

--

9

Replace the underhood accessory junction block. Refer to Relay/Fuse Center Replacement in Wiring Systems.

Has the repair been completed?

--

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you complete the repair?

--

System OK

Go to Step 2

Headlamps Inoperative - One Lamp Export

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2
    • For the low beam, verify that only one low beam headlamp is inop.
    • For the high beam, verify that only one high beam headlamp is inop.

Are both low beam or both high beam headlamps inop?

--

Go to Headlamps Inoperative - Low Beams or Headlamps Inoperative - High Beams

Go to Step 3

3
  1. Disconnect the inoperative headlamp connector.
  2. Turn the headlamp switch to the HEAD position.
  3. Complete the following steps if the low beam is inoperative:
    4. • Turn the headlamp dimmer switch to the LOW position.
    • Use a test lamp in order to backprobe from the inoperative headlamp connector terminal B to ground.
  4. Complete the following steps if the high beam is inoperative:
    5. • Turn the headlamp dimmer switch to the HIGH position.
    • Use a test lamp in order to backprobe from the inoperative headlamp connector terminal C to ground.

Did the test lamp light?

--

Go to Step 4

Go to Step 5

4
    • If the low beam is inoperative, use a test lamp in order to frontprobe the inoperative headlamp connector B to headlamp connector A.
    • If the high beam is inoperative, use a test lamp in order to frontprobe the inoperative headlamp connector C to headlamp connector A.

Did the test lamp light?

--

Go to Step 7

Go to Step 8

5
  1. Complete the following steps for the left headlamp:
    2. • For the low beam, use a test lamp in order to backprobe between the underhood electrical center connector C3 terminal A8 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood electrical center connector C3 terminal A4 and ground.
  2. Complete the following steps for the right headlamp:
    3. • For the low beam, use a test lamp in order to backprobe between the underhood electrical center connector C3 terminal A12 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood electrical center connector C3 terminal E11 and ground.

Did the test lamp light?

--

Go to Step 6

Go to Step 9

6
    • For the low beam, repair an open in CKT *12 between the underhood electrical center connector and the inoperative headlamp connector terminal B.
    • For the high beam, repair an open in CKT *11 between the underhood electrical center connector and the inoperative headlamp connector terminal C.

Has the repair been made and the system rechecked?

--

Go to Step 12

--

7

Replace the headlamp. Refer to Headlamp Assembly or Headlamp Bulb Replacement .

Has the repair been made and the system rechecked?

--

Go to Step 12

--

8
    • For the left headlamp, repair an open in CKT 1350 between the headlamp connector terminal A and G101.
    • For the right headlamp, repair an open in CKT 1250 between the headlamp connector terminal A and G102.

Has the repair been made and the system rechecked?

--

Go to Step 12

--

9
  1. Complete the following steps for the left headlamp:
    2. • For the low beam, use a test lamp in order to backprobe between the underhood electrical center connector C2 terminal F8 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood electrical center connector C2 terminal F4 and ground.
  2. Complete the following steps for the right headlamp:
    3. • For the low beam, use a test lamp in order to backprobe between the underhood electrical center connector C2 terminal F12 and ground.
    • For the high beam, use a test lamp in order to backprobe between the underhood electrical center connector C2 terminal E11 and ground.

Did the test lamp light?

--

Go to Step 10

Go to Step 11

10

Replace the underhood electrical center. Refer to Relay/Fuse Center Replacement in Wiring Systems.

Has the repair been made and the system rechecked?

--

Go to Step 12

--

11
    • For the left low beam, repair an open in CKT 712 between the underhood electrical center connector C2 terminal F8 and the fuse block terminal C4.
    • For the left high beam, repair an open in CKT 711 between the underhood electrical center connector C2 terminal F4 and the fuse block terminal B4.
    • For the right low beam, repair an open in CKT 312 between the underhood electrical center connector C2 terminal F12 and the fuse block terminal C2.
    • For the right high beam, repair an open in CKT 311 between the underhood electrical center connector C2 terminal E11 and the fuse block terminal B2.

Has the repair been made and the system rechecked?

--

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you complete the repair?

--

System OK

Go to Step 2