GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

An intermittent malfunction may be caused by a fault in the magnetic clutch electrical circuit. Inspect the wiring harness and components for any of the following conditions:

    • Backed out terminals
    • Improper mating of terminals
    • Broken electrical connectors locks
    • Improperly formed or damaged terminals
    • Faulty terminal to wire connections
    • Physical damage to the wiring harness
    • A broken wire inside the insulation
    • Corrosion of electrical connections, splices, or terminals

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for proper arm movement with the magnetic clutch de-energized.

  2. This step tests for proper arm movement with the magnetic clutch energized.

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

1

Did you perform the Diagnostic System Check - Cruise Control ?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2

  1. Disconnect the cruise control cable from the actuator.
  2. Move the actuator arm back and forth.

Does the actuator arm move freely in both directions?

Go to Step 3

Go to Step 5

3

  1. Disconnect the cruise control servo connector.
  2. Connect a fused jumper wire from ground to terminal 4 of the cruise control servo.
  3. Connect a fused jumper wire from B+ to terminal 3 of the cruise control servo.
  4. Attempt to move the actuator arm.

Does the actuator arm move?

Go to Step 5

Go to Step 4

4

Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

--

5

Inspect for poor connections at the harness connector of the cruise control servo. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

--

6

Replace the cruise control module. Refer to Cruise Control Module Replacement .

Did you complete the replacement?

Go to Step 8

--

7

Replace the cruise control servo. Refer to Cruise Control Servo Replacement .

Did you complete the replacement?

Go to Step 8

--

8

  1. Turn OFF the ignition.
  2. Remove the STOP fuse.
  3. Remove the ECU-B fuse.
  4. Wait 30 seconds.
  5. Reinstall STOP and ECU-B fuses.
  6. Turn ON the ignition, with the engine OFF.
  7. Using the jumper, connect the DLC terminals Tc and E1.

Does the CRUISE indicator lamp flash the same trouble code?

Go to Step 2

System OK