GM Service Manual Online
For 1990-2009 cars only

With the ignition switch in RUN, battery positive voltage (B+) is applied on CKT 141 (BRN) to terminal F of the cruise control module. Moving the CRUISE switch to the ON position applies battery positive voltage (B+) on CKT 397 (GRY) to terminal A of the cruise control module. If the brake pedal is released, battery positive voltage (B+) is applied on CKT 420 (PPL) at the cruise control module terminal D. If the brake pedal is depressed, battery positive voltage (B+) is present on CKT 20 (LT BLU) at the cruise control module terminal G.

When the CRUISE switch is moved to the R/A position, battery positive voltage (B+) is applied on CKT 87 (GRY/BLK) to terminal C of the cruise control module. When the SET button is pressed, battery positive voltage (B+) is applied on CKT 84 (DK BLU) at terminal B of the cruise control module. The PCM supplies the vehicle speed signal on CKT 817 (DK GRN/WHT) to terminal K of the cruise control module. In operation, the vehicle speed signal voltage oscillates between a high of battery positive voltage (B+) and a low of 0.5 V. The cruise control module ground is connected on CKT 51 (BLK/WHT) to ground. The cruise control engaged output signal is supplied to the PCM on CKT 85 (WHT) at terminal J of the cruise control module. The cruise inhibit signal from the PCM on CKT 83 (DK GRN) to terminal H of the cruise control module.

The PCM has the ability to disable the cruise control if conditions are detected which would make cruise control operation undesirable. The PCM inhibits cruise control operation under any of the following cruise control inhibit conditions:

    • The engine is off.
    • The transaxle is in PARK, NEUTRAL, LOW or REVERSE gear.
    • Engine speed is too high.
    • Vehicle speed is too high.
    • Vehicle acceleration or deceleration rate is too high.
    • Antilock brake system/traction control system is active for more than 2 seconds.

If the PCM determines that any of the cruise control inhibit conditions are present, the PCM requests that the cruise control module disengage cruise control. The PCM accomplishes this request by grounding CKT 83 (DK GRN). The cruise status signal is sent by the cruise control module to the PCM on CKT 85 (WHT). If the cruise status signal indicates that the cruise control is still engaged after the PCM has requested that cruise control disengage, the PCM sets a DTC.