How to Rewire a Truck-Mounted Man Lift

Truck-mount man lifts are used to service and repair overhead lines.

Man lifts for utility trucks consist of an electric motor and a hydraulic boom with a worker’s basket. The motor rotates the base of the boom, and controls in the basket allow you to operate the boom and position the basket. Industrial mishap and use in extreme conditions can damage the motor wiring, to the point that replacement is necessary. Obtain the primary and secondary wire harnesses from the manufacturer, based on the model of the unit, to rewire a truck-mount man lift.

Things You'll Need

• 22-gauge primary wire harness
• 22-gauge secondary wire harness with jumper wires
• Screwdriver

Instructions

Primary Wiring

1. Remove the covers at the accessory adapter board and the lift control module with a screwdriver.

2. Detach the original integral 5-wire connector from the accessory board by depressing tabs on the side of the connector by hand. Push the integral 5-wire connector the new 22-gauge primary wire harness onto the accessory board so it snaps into place.

3. Trace the path of each wire from the original integral connector to the connections at the lift module control. Detach the single connectors at the end of each wire, one at a time, as you connect the similar color wires from the new primary harness to the corresponding tabs on the module.

4. Discard the original wire harness. Reattach the covers at the accessory board and the module control.

Secondary Wiring

1. Remove the access panel at the side of the motor case with a screwdriver.

2. Detach the single wire connector from the rotary position sensor at the underside of the motor-actuating lever. Connect the single connector on the new 22-gauge secondary wire harness to the position sensor.

3. Detach the opposite end of the original wire harness from the intermediate connector near the digital counter at the motor compartment. Attach the single connector on the opposite end of the new secondary wire harness to the intermediate connector.

4. Position the new jumper wires and the integral 3-wire connector at the intermediate connector and the nearby digital counter. Detach each jumper wire connector at the counter, one at a time, as you connect the similar color jumper wires to the corresponding tabs on the counter. Discard the original wiring.

5. Detach the original 3-wire integral jumper connector from the intermediate wire connector. Attach the new 3-wire integral jumper connector to the intermediate connector. Reattach the access panel at the motor case.

Tips & Warnings

• Wiring and wire harnesses differ slightly with larger and smaller man lifts. If necessary, obtain a wiring diagram for the man lift from the manufacturer.

• Disconnect the battery cables before you rewire the man lift.

References

• Tag Truck Center: Freightliner Utility Trucks
• Ramsey Winch Company: Ram-Lift Crane Owner’s Manual
• Braun Lift: Braun Man Lift Owner’s Manual – Page 12: Lift Wiring Diagram