How do you set timing on 2000 sierra 1500 5.3?

To set the timing on a 2000 Sierra 1500 with a 5.3L engine, first ensure the vehicle is on a level surface and the engine is at operating temperature. Disconnect the timing connector (usually a brown wire) to put the ignition control module in base timing mode. Then, use a timing light to check the timing marks on the harmonic balancer against the timing tab; the correct timing is typically around 0 degrees BTDC. Adjust the distributor as needed to align the marks, then reconnect the timing connector when finished.