- Diagnostic test light
- Loom connector
- Installation hardware
This unit once connected with the switch in the off position it will act as an engine fault warning light. When a fault is detected the light will illuminate, then if the vehicle is switched off and then the ignition is turned back on (without the engine running) and the switch is depressed the diagnostic trouble code (DTC) will be flashed out starting with the lowest code number first.
The codes can then be referenced to the GM manual or in the chart provided in our instructions.