Steer mode control unit 704/21600 JCB 3CX/4CX, aftermarket

Steer mode control unit 704/21600 is an aftermarket part for the JCB 3CX and 4CX backhoe loaders.

This control unit (relay box) manages the steering modes on JCB machines with all-wheel steer: two-wheel steer, four-wheel steer and crab steer. When the operator selects a mode with the cab switch, the unit drives the solenoids of the steer mode valve and, using the signals from the wheel position sensors, allows a mode change only with the wheels aligned. A faulty unit may not change mode, stay in the wrong mode or let the wheels lose alignment. Check the fuse, sensors and connectors before replacing the unit. If the unit takes its earth through its metal case, the contact face must be clean.

Specifications

Compatibility

The catalogue also has the genuine version of this part. Other parts are in Control units.

Fitting

Moisture and corrosion inside the connector are a common cause of false signals from sensors and switches, so clean the connector and use contact spray if needed. Renew the connector seal if it is missing. The part is chosen by part number, and its connector type is compared with the old part.