Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
All electrical components and accessories must be turned OFF and allowed to power down.
- Ignition OFF, disconnect the harness connector at the solid state relay module.
- Test for less than 5 ohms of resistance between the ground circuit terminal B and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, test for 4.85 - 5.2 volts between the 5-volt reference circuit terminal C and ground.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the TBCM.
- If all circuits test normal, replace the trailer brake solid state relay.