Cruise Control Unit
- Ensure brakelight/cruise control fuse is okay. Remove passenger's seat. Disconnect wiring harness from cruise control unit. Connect voltmeter negative lead to connector pin No. 12, and positive lead to pin No. 1. See Fig 1
. Turn ignition on. Ensure battery voltage is present.
- Connect voltmeter negative lead to connector pin No. 12, and positive lead to pin No. 3. Ensure battery voltage is present. Press off key on cruise control switch. Ensure reading changes to zero volts.
- Connect voltmeter negative lead to connector pin No. 12, and positive lead to pin No. 4. Ensure reading is zero volts. Press on/accelerate key on cruise control switch. Ensure reading changes to battery voltage.
- Connect voltmeter negative lead to connector pin No. 12, and positive lead to pin No. 6. Ensure reading is zero volts. Press record key on cruise control switch. Ensure reading changes to battery voltage.
- Connect voltmeter negative lead to connector pin No. 12, and positive lead to pin No. 8. Ensure reading is zero volts. Press and hold brake pedal. Ensure reading changes to battery voltage.
- Connect voltmeter negative lead to connector pin No. 14, and positive lead to pin No. 1. Ensure battery voltage is present. Press and hold clutch pedal (if equipped). Ensure reading changes to zero volts.
- Connect oscilloscope to connector pins No. 11 and 12. Turn left rear wheel by hand. Ensure oscilloscope displays square wave signals. If readings are not as specified, ensure wiring harness to cruise control unit is okay. If necessary, replace cruise control unit.
Courtesy of PORSCHE OF NORTH AMERICA, INC.