Shift Light (Manual Transmission)

These tests assume a shift light problem exists. Use this procedure only if the light will not illuminate, or illuminates all the time.
Turn ignition on, with engine off. Note shift light. Shift light should not be on. If shift light is on, check for a short to ground between bulb and ECM/PCM/VCM or for bad ECM/PCM/VCM.
With ignition on and engine off, ground test terminal "B" of Data Link Connector (DLC). Malfunction Indicator Light (MIL) should start to flash and shift light should come on. If MIL comes on, go to next step. If MIL does not flash, perform DIAGNOSTIC CIRCUIT CHECK as described in BASIC TESTING - 4.3L article.
If shift light does not come on, ground Tan/Black light driver wire at ECM/PCM/VCM terminal using a jumper wire. For circuit identification, see SHIFT LIGHT CIRCUIT IDENTIFICATION below, and Fig 1.
If shift light still does not come on, check for blown GAGES fuse, blown bulb or open circuit between fuse and ECM/PCM/VCM. If shift light comes on when grounding ECM/PCM/VCM terminal with a jumper wire, problem is a bad ECM/PCM/VCM connection or bad ECM/PCM/VCM.

SHIFT LIGHT CIRCUIT IDENTIFICATION

Fig 1: Typical Shift Light Circuit (All Models)

Courtesy of GENERAL MOTORS CORP.