Speedometer/Odometer Inoperative (Commercial & Motorhome)
- Disconnect instrument cluster connector. Disconnect vehicle control module. VSS buffer is located under bracket bolted to left side of interior bulkhead. Vehicle Control Module (VCM) is located on left radiator support. Measure resistance in Dark Green wire between instrument cluster connector terminal No. 28 and VSS buffer terminal No. 15 or VCM terminal No. 4. If resistance is less than .5 ohm, go to next step. If resistance is greater than one ohm, repair open circuit in Dark Green wire.
- Measure resistance between instrument cluster connector terminal No. 28 and ground. If resistance is greater than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire.
- Measure voltage between instrument cluster connector terminal No. 28 and ground. If more than one volt is present, repair short to voltage in Dark Green wire. If less than one volt is present, check all fuses and wiring for an open circuit.