GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Safari - 2WD 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlamp and Panel Dimmer Switch Inoperative
 

Action

Value(s)

Yes

No

1

Did you perform the Lighgting Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Check the following fuses.

    • 40A Lighting fuse #8 at the underhood fuse block.
    • 20A Park Lamps fuse at the I/P fuse block Fuse #9.
    • RH headlamp fuse at the underhood fuse block.
    • LH headlamp fuse at the underhood fuse block center.
    • 14A Illumination fuse #14 at the I/P fuse block.
    • 3A courtesy fuse #20 at the I/P fuse block

Are all of the fuses functional?

--

Go to Step 4

Go to Step 3

3

Locate and repair any overloads present and replace inoperative fuse(s).

Is the repair complete?

--

Go to Step 11

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4
  1. Turn the headlamp switch to the HEAD postion.
  2. Disconnect the headlamp and panel dimmer switch connector.
  3. With DMM, check for battery voltage at the headlamp switch connector cavitiy D CKT 1840 (ORN) and cavity B CKT 240 (ORN).

Is battery voltage present?

B+

Go to Step 6

Go to Step 5

5

Locate and repair the OPEN in one of the following CKT's:

    • CKT 1840 (ORN) between the headlamp switch and I/P fuse block.
    • CKT 240 (ORN) between the headlamp switch and the I/P fuse block.

Is the repair complete?

--

Go to Step 11

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6
  1. Reconnect the headlamp switch.
  2. Leave the headlamp switch in the HEAD position.
  3. Check for battery voltage with DMM at cavity C CKT 352 (WHT) and cavity H CKT 549 (PPL/WHT).

Is battery voltage present?

B+

Go to Step 8

Go to Step 7

7

Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement

Is the repair complete?

--

Go to Step 11

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8
  1. Turn ON the dome lamps with headlamp switch.
  2. Check for battery voltage at cavity G CKT 1495 (DK BLU/WHT).

Is battery voltage present?

B+

Go to Step 9

Go to Step 7

9

Check continuity of CKT 750 (BLK) from cavity E to ground G110.

Is continuity present?

--

Go to Step 7

Go to Step 10

10

Locate and repair OPEN in CKT 750 (BLK) between the headlamp switch and ground G110.

Is the repair complete?

--

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2