Some units of the GMC Terrain may experience a range of electrical issues as a result of water intrusion in the taillights.
Per a report from GM TechLink, some of these issues include a no start or extended crank condition, a dead battery, a fuel pump that runs when the ignition is off, and a Service Safety Restraints message on the Driver Information Center. Additionally, the issue may trigger Diagnostic Trouble Code (DTC) P12A6 (Fuel Pump Driver Control Module Enable Circuit Performance) or DTC B0073 (Passenger Seat Belt Switch Circuit).
According to the report, these conditions may occur as a result of water intrusion in the GMC Terrain right-side taillight due to a broken lens or housing. Water may travel through the bulb connector wire strands to the X350 connector, X320 connector, or Body Control Module (BCM). Units of the GMC Terrain from the 2018 through 2023 model years may be affected.
If these conditions are encountered, it’s recommended that the GMC Terrain taillight bulb connectors are inspected for possible water corrosion. The taillight and bulb connector should be replaced if corroded.
In the event that DTC P12A6 is triggered, connector X350 (Fuel Tank Harness to Body Harness) should be checked, as water corrosion may short the terminals together, resulting in the fuel pump to run after the ignition is turned off, thus draining the battery and leading to a no start or extended crank condition. In the event that water intrusion or corrosion is discovered, replace the connector with terminated leads on the body harness side, and /or replace the fuel pump module harness.
Check connector X320 (Right Front Seat Harness to Body Harness connector) if DTC B0073 is triggered or the Service Safety Restraints message is seen on the DIC. Be sure to disable the SIR system prior to inspection. If water damage is discovered, also check the BCM connector for signs of water intrusion. If water intrusion is found, add dielectric grease to the connector and continue the diagnosis as required. More information can be found in reference to Bulletin #22-NA-170.