Instrument Cluster Illumination Lamps Inoperative. GMC Truck Safari

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Safari - 2WD 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Instrument Cluster Illumination Lamps Inoperative

Step

Action

Value(s)

Yes

Important: The following devices are controlled by the headlamp and panel dimmer switch via CKT 8 (GRY):

•

Radio

•	Remote CD player (if equipped)

•	Instrument Cluster

•	Heater and A/C Control Module

•	Rear Window/Wiper Washer Switch (if equipped)

•	Overhead Console (if equipped)

•	Rear Heater Switch (if equipped)

•	Rear A/C Switch (if equipped)

CKT 8 (GRY) also has an input to the Body Control Module (BCM), which goes to an internal rheostat in the BCM. This rheostat controls the L.E.D. dimming signal. This output exits the BCM via CKT 1382 (PPL/WHT). This signal goes to the following two modules:

•

Radio

•	Overhead Console

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Position the headlamp switch to the PARK position.
Vary the panel dimmer switch at the headlamp and panel dimmer switch from dim to the full intensity.
Observe the intensity of the following components (if equipped).

•

Radio

•	Remote CD Player

•	Instrument Cluster

•	Heater and A/C Controls

•	Rear Window/Wiper Switch

•	Overhead Console

•	Rear Heater Switch

•	Rear A/C Switch

Are the components operating correctly?

Go to Step 3

Go to Step 4

Position the headlamp switch to the PARK position.
Vary the panel dimmer switch at the headlamp and panel dimmer switch from dim to the full intensity.
Observe the intensity of the following two components (if equipped).

•

Radio

•	Overhead Console

Is the L.E.D. dimming signal operating correctly?

Go to Step 16

Go to Step 13

Are all of the dimming components inoperative?

Go to Step 8

Go to Step 5

Position headlamp switch to the PARK posiiton.
Set the dimmer switch to full intensity.
Use a test lamp to check for power from the inoperative module CKT 8 (GRY) to ground.

Does the test lamp light?

Go to Step 6

Go to Step 7

Locate and repair the OPEN between the inoperative component and it's respective ground.

(Replace the component if no wiring fault is found).

Is the repair complete?

Go to Step 16

Locate and repair the OPEN in CKT 8 (GRY) between the inoperative component and splice S219.

Is the repair complete?

Go to Step 16

Check ILLUM fuse 14 at the I/P fuse block.

Is fuse functional?

Go to Step 10

Go to Step 9

Locate and repair overload and replace ILLUM fuse 14 at the I/P fuse block.

Is the repair complete?

Go to Step 16

Check the following two wires for continuity:

•	CKT 44 (DK GRN) between the headlamp and panel dimmer switch and the I/P fuse block

•	CKT 8 (GRY) between the I/P fuse block and splice S219

Are both wires functional?

Go to Step 11

Go to Step 12

Replace the headlamp and panel dimmer switch Headlamp Switch Replacement

Is the repair complete?

Go to Step 16

Locate the OPEN and repair the faulty circuit.

Is the repair complete?

Go to Step 16

Set the dimming switch to full intensity.
Connect a test lamp from connector C2, cavity A12 of the Body Control Module (BCM) to ground.
Vary the dimmer switch from full intensity to low intensity.

Does the test lamp vary in brightness/or operate?

Go to Step 15

Go to Step 14

Refer to the BCM Diagnostic System Check Diagnostic System Check - Body Control System

Is the repair complete?

Go to Step 16

Check the functionality of the following two wires:

•	CKT 1382 (PPL/WHT) between the BCM and the radio

•	CKT 1382 (PPL/WHT) between the BCM and the Overhead Console

Is the repair complete?

Go to Step 16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2