Circuit/System Testing

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

Ignition OFF/vehicle OFF, disconnect the harness connector at the A20 Radio/HVAC Controls.
Test for less than 10 Ω between the following low reference circuit terminal 10 and ground.
- If 10 Ω or greater
1. Disconnect the X1 harness connector at the P17 Info Display Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the P17 Info Display Module.
- Go to next step: If less than 10 Ω
Ignition ON/vehicle in Service Mode, test for 2.5 - 3.5 V between the following signal circuit terminals and ground:
- Terminal 5 @ A20 Radio/HVAC Controls Harness
- Terminal 6 @ A20 Radio/HVAC Controls Harness
- Terminal 7@ A20 Radio/HVAC Controls Harness
- Terminal 8 @ A20 Radio/HVAC Controls Harness
- If less than 2.5 V
1. Ignition OFF/vehicle OFF, disconnect the X1 & X2 harness connectors at the A11 Radio.
2. Test for infinite resistance between the following signal circuits and ground:
  - Terminal 5 @ A20 Radio/HVAC Controls Harness
  - Terminal 6 @ A20 Radio/HVAC Controls Harness
  - Terminal 7@ A20 Radio/HVAC Controls Harness
  - Terminal 8 @ A20 Radio/HVAC Controls Harness
  - If less than infinite resistance repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω between the following test points:
  - Terminal 5 @ A20 Radio/HVAC Controls Harness & Terminal 3 X2 @ A11 Radio Harness
  - Terminal 6 @ A20 Radio/HVAC Controls Harness & Terminal 8 X1 @ A11 Radio Harness
  - Terminal 7 @ A20 Radio/HVAC Controls Harness & Terminal 8 X2 @ A11 Radio Harness
  - Terminal 8 @ A20 Radio/HVAC Controls Harness & Terminal 9 X2 @ A11 Radio Harness
  - If 2 Ω or greater repair the open/high resistance in the circuit.
  - If less than 2 Ω replace the A11 Radio.
- If greater than 3.5 V
1. Ignition OFF/vehicle OFF, disconnect the X1 & X2 harness connectors at the A11 Radio.
2. Test for less than 1 V between the following signal circuits and ground:
  - Terminal 5 @ A20 Radio/HVAC Controls Harness
  - Terminal 6 @ A20 Radio/HVAC Controls Harness
  - Terminal 7 @ A20 Radio/HVAC Controls Harness
  - Terminal 8 @ A20 Radio/HVAC Controls Harness
  - If greater than 1 V repair the short to voltage in the circuit.
  - If less than 1 V replace the A11 Radio.
- Go to next step: If between 2.5 - 3.5 V
Replace the A20 Radio/HVAC Controls