Multifunction relay 4RD007794021, aftermarket

Multifunction relay 4RD007794021 is an aftermarket part for the construction machines. On the product card the relay is described as multifunction; the circuit it controls and the machine are not given. Compare the number and pin layout with the old relay.

A relay lets a small current control a heavy circuit: current from a switch or control unit flows through the relay coil, and its contacts switch the current of the load, such as lamps, starter, heating, horn or fan. This keeps switches and electronics from being overloaded and keeps power cables short. Multifunction relays combine several functions in one housing, for example interval operation and switch-off delay, and work to a built-in circuit. A faulty relay fails to switch the load on, fails to switch it off or works intermittently. The pin layout is shown on the relay body or the socket; the new relay goes into the old relay's socket the same way round.

Specifications

Compatibility

According to the product card, the part number is 4RD007794021. Fit is confirmed by the part number and the machine serial number. Other parts are in Relays.

Fitting

Change the relay with the ignition off; push the pins fully home and check that the socket contacts are neither spread nor corroded.