Multi-function unit (MFU) – circuit operation rev: 11/97

MULTI-FUNCTION UNIT (MFU) – CIRCUIT OPERATION REV: 11/97

CIRCUIT OPERATION

Multi-Function Unit (MFU)

The multi-function unit (MFU) is mounted on the rear of the passenger compartment fusebox and has an input to operation of the following: Heated rear screen
Heated front screen
Courtesy lights
Side and headlights
Rear fog guard lamps
Headlamp power wash
Front wipers
Rear wash/wipe

Diagnostic Procedure

1. Close all doors and the tailgate.

NOTE: If the oil pressure switch goes open circuit (engine is started) during the following procedure, the MFU will exit the diagnostic mode immediately.

2. Press and hold the heated rear screen switch and switch on the ignition. 3. Release the heated rear screen switch within 2 seconds and the MFU will beep to indicate that it’s in diagnostic mode 1. 4. Press the heated rear screen switch; the MFU will beep twice. In turn, operate each of the following switches, heated front screen, rear fog guard lamps, side lights, headlights, front wiper, and rear wiper. The MFU will beep twice each time a switch is operated. 5. Pressing the heated rear screen again will cause the MFU to enter diagnostic mode 2. 6. The MFU will provide outputs to the following in order given below: Heated rear screen relay energised for 2 seconds
Heated front screen energised for 2 seconds
Courtesy lights energised for 2 seconds
Dim dip relay energised for 2 seconds
Rear fog guard lamp energised for 2 seconds
Headlamp power wash energised for half a second
Front wiper energised for half a second
Rear wipe/wash energised for half a second
7. The MFU will then exit the diagnostic mode.