Code
B2474
HUMMER
B — Body
Navigation Display Head (NDH) Back Lighting Malfunction
AI status
Completed
Completed
100%
Causes
- Failed NDH backlight (LED array or driver)
- Blown fuse for radio/navigation/display circuit
- Open, short, or high resistance in power or ground wiring to NDH
- Corroded or loose connector at NDH or body harness
- Faulty dimmer/illumination control or wrong setting
- Body control module (BCM) or NDH internal electronics/software fault
Symptoms
- Navigation display backlight is completely off
- Display is dim or unevenly lit
- Backlight flickers or varies with engine speed/lighting
- Warning message on display about illumination
- Other interior lighting behaves abnormally (if shared circuit)
What to check
- Retrieve all stored codes with a scan tool and note freeze frame/related codes
- Visually inspect fuse(s) for radio/NDH and interior illumination; verify correct fuse rating
- Inspect NDH harness connector for corrosion, bent pins, or water intrusion
- Check for related symptoms on other illuminated components (cluster, radio) to identify shared circuit
- Verify dimmer/illumination control position and operation
- Check for recent wiring repairs or water leaks near dash and NDH area
Signal parameters
- Backlight supply voltage (key ON): approx. 11–14 V (or PWM 0–12 V depending on design)
- Backlight ground continuity: < 2 ohms to chassis
- PWM dimming (if used): present on control pin, typical frequency 100–1000 Hz and duty cycle varies with dimmer
- CAN/LIN messages: NDH and BCM communication present and error-free when scanning
Diagnostic algorithm
- Connect a diagnostic scan tool, read and record B2474 and any other codes; clear codes and attempt to reproduce.
- Inspect fuses related to the radio/NDH and interior lighting; replace suspect fuses and retest.
- Visually inspect NDH connector and harness for damage, corrosion, moisture, or pin push-out; repair as necessary.
- With key ON, backprobe the NDH backlight power and ground pins: verify supply voltage (~11–14 V) and good ground. If no supply, trace back to fuse/relay/BCM.
- If supply present but backlight off, check for PWM dimming signal from dimmer/BCM on the control pin. Use oscilloscope or multimeter (duty cycle change with dimmer).
- Wiggle test harness and connectors while observing backlight for intermittent faults.
- If wiring and control signals are correct but backlight remains faulty, remove NDH and bench-test or replace the NDH assembly/LED driver per vendor procedure.
- If intermittent or communication-related, inspect CAN/LIN wiring and perform module communication tests; reflash/update NDH/BCM software if a technical service bulletin (TSB) recommends.
- After repair, clear codes and verify system operation under all lighting/dimmer conditions; perform road test if necessary.
Likely causes
- Open or short in backlight power feed or ground
- Failed LED driver inside the NDH assembly
- Blown or weak fuse protecting the NDH supply
- Poor connector contact or corrosion at NDH harness
- Faulty instrument panel dimmer switch or BCM output
Fault status
Status
NDH back lighting malfunction detected — inspect NDH assembly, illumination circuit, and related controls.
Repair difficulty: Medium
Diagnostic time: 0.8-2.0 hours
Similar codes
Repair manuals
Manual library for HUMMER
138
Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
HUMMER
-
HUMMER: 2009
-
HUMMER: 2008
-
HUMMER: 2007
-
HUMMER: 2005
-
HUMMER: 2004
-
HUMMER: 2000
-
HUMMER: 1999
-
HUMMER: 1994
-
HUMMER: 1993
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email