Backup Light and Clutch Switches

Two switches associated with a manual transmission are the clutch start and backup light switch. A clutch start switch is often called a clutch safety switch. They are both simple switches; they are either on or off. Both of these switches can be diagnosed with a jumper wire and an ohmmeter.

The clutch safety switch is either located on the clutch pedal or on the clutch masters push rod. This switch runs in series with the starter relay preventing starter engagement when the switch is left open. The switch is in its normally open position when the pedal is released. When the clutch pedal is depressed the switch closes completing the circuit. In this position power runs in series through the ignition switch, the clutch switch, the starter relay, and then to the starter solenoid. The vehicles starter will then engage.

If this switch is suspected in a no start situation make sure the pedal is correctly adjusted and the fuse is good. Be safe and make sure the vehicle is in neutral, emergency brake is on, and the tires are chocked. Disconnect the connector to the switch. Place a jumper wire across the connector terminals and then attempt to start the vehicle. If the vehicle then starts the switch was stuck in the open position.

Use an ohmmeter to test the switch. The button type switch will be located on the clutch pedal. When the switch is left out in its normally open position the meter will read infinity (~). When the button is pushed in the meter will show a reading of continuity; likely (0.00). This indicates a good switch.

The backup light switch is located on the transmission case and completes the circuit to the backup lights only when the transmission is shifted into reverse. This switch is greatly affected by the shifter linkage. If both backup lights are inoperative check the linkage and the related fuse before testing the switch.

The same series of tests are used to diagnose this switch as with the clutch switch. If the lights suddenly work when the connector is jumped suspect an open switch. The ohmmeter will verify this diagnosis. If a single bulb is out suspect the bulb, the connector, or the associated wiring unique to that bulbs circuit.