Circuit/System Verification

WARNING: This page is about a different car, the 2018 GMC Canyon and 2018 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON.
Verify the scan tool LED Backlight Dimming Command parameter changes between a high percentage to a low percentage while operating the dimmer switch from high to low.
- If the parameter does not change
  Refer to Circuit/System Testing Dimmer Switch Malfunction.
- Go to next step: If the parameter changes
Verify the switch indictor amber LED's for the components listed below turn ON and OFF while turning both switches ON and OFF.
- S48A Multifunction Switch - Instrument Panel (lane departure switch)
- S77 Transfer Case Shift Control Switch
- S79D Window Switch - Driver (child safety lock switch)
- If the switch indicator amber LED's do not turn ON and OFF
  Refer to Circuit/System Testing Switch Indicator LED Backlighting Malfunction.
- Go to next step: If the switch indicator amber LED's turn ON and OFF
Verify all backlighting components turn ON and OFF while commanding the LED Backlight Dimming ON and OFF with a scan tool.
- If all backlighting components do not turn ON and OFF
  Refer to Circuit/System Testing Interior Backlighting Malfunction.
- Go to next step: If all backlighting components turn ON and OFF
Verify the phrase PASSENGER AIR BAG is illuminated on the Passenger Air Bag Disable Indicator.
- If the phrase PASSENGER AIR BAG is not illuminated
  Refer to Circuit/System Testing Passenger Air Bag Disable Indicator Backlighting Malfunction.
- Go to next step: If the phrase PASSENGER AIR BAG is illuminated
All OK.