Converter Lock-Up Signal From ECM

Warm engine to operating temperature. Raise vehicle and support drive wheels. Support suspension where necessary to prevent damage to drive axles.
Connect a test light to battery voltage. Touch TCC control driver terminal with test light. On some vehicles this is terminal "F" of the ALDL connector. See Fig 1 & Fig 2 . Accelerate vehicle to 45 MPH and note test light. If test light does not illuminate, problem is a faulty ECM connector or ECM.

Fig 1: Converter Clutch Schematic, (3.8L)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Converter Clutch Schematic, (4.9L)

Courtesy of GENERAL MOTORS CORP.