Circuit/System Testing

Rear Compartment Lid Release Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the S58A rear compartment lid unlatch switch-exterior.
2. Test for less than 10 Ω between the ground circuit terminal 3 and ground
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify the scan tool Interior Trunk Lid/Liftgate Window Unlatch Switch parameter is Inactive.
   • If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Interior Trunk Lid/Liftgate Window Unlatch Switch parameter is Active.
   • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, test or replace the S58A rear compartment lid unlatch switch-exterior.

Rear Compartment Lid Malfunction

1. Ignition OFF, disconnect the harness connector at the M40 rear compartment lid latch.
2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
   • If greater than the specified range, test the ground circuit for and open/high resistance.
3. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2.
4. Ignition ON, command the M40 rear compartment lid latch to UNLATCH with a scan tool. The test lamp should briefly illuminate during the UNLATCH command.
   • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the X50A fuse block-underhood.
   • If the test lamp is always OFF and the B+ circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the M40 rear compartment lid latch.
   • If the test lamp is always OFF and the B+ circuit fuse is normal, test the control circuit for an open/high resistance. If the circuit tests normal, refer to Underhood Fuse Block Test.
5. If all circuits test normal, test or replace the M40 rear compartment lid latch.

Underhood Fuse Block Test

1. Ignition OFF, disconnect the X1 harness connector at the X50A fuse block-underhood.
2. Test for less than 10 Ω between the ground circuit terminal 71 and ground.
   • If greater than the specified range, test the ground circuit for and open/high resistance.
3. Connect the X1 harness connector at the X50A fuse block-underhood.
4. Disconnect the X5 harness connector at the K9 BCM.
5. Ignition ON, test for less than 1 V between the control circuit terminal 11 and ground
   • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the X50A fuse block-underhood.
6. Ignition ON, connect a 10 A fused jumper wire between the control circuit terminal 11 and B+. Verify the M40 rear compartment lid latch is activated.
   • If the M40 rear compartment lid latch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the X50A fuse block-underhood.
7. If all circuits test normal, replace the K9 BCM.