Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.

NOTE:

The test lamp in the following step will illuminate at LOW intensity. This is normal circuit operation and does not indicate a circuit malfunction.

Verify a test lamp illuminates between the control circuit terminal 18 and ground.
- If the test lamp does not illuminate
1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
2. Test for infinite resistance between the control circuit terminal and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the X50A Fuse Block - Underhood.
- If the test lamp illuminates
Ignition OFF, connect a 3 A fused jumper between the control circuit terminal 18 and ground, ignition ON, low beam headlamps ON.
Verify the high beam headlamps illuminate.
- If the high beam headlamps do not illuminate
1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, ignition ON.
2. Test for less than 1 V between the control circuit terminal 18 and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the X50A Fuse Block - Underhood.
- If the high beam headlamps illuminate
Test or replace the K9 Body Control Module.