Hi guys iv had a quick look through previous posts and some sound similar to my problem but nothing identical....... few weeks ago my indicators and brake lights stopped working but the hazards still worked, so the next day i found a blown fuse so i replaced and all worked fine for a couple of weeks then the indicators suddenly went again but the brake lights carried on working??? whan i put the hazards on the hazard light button just stays lit up without any flashing but none of the lights on the outside are lit up? i thought it may have been a fuse again so checked them all and nothing so someone suggested the relay so i bought a brand new one and nothing so im out of ideas now? all seems fine on the stalk clicks like it should..... any suggestions?:doh:
sierrafery
Well-Known Member
For Disco 1 could be the fookin freaky thing named (MFU)Multi Functional Unit, part of the inside fuse box, it usually develops so cold "dry joints", it has a diagnostic procedure as follows:
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 its 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 oper-ated.
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.
It will not help if there is a dry joint, this one must be located and fixed with a soldering gun
For Disco 2 its an even freakyer thing named BCU, this one is diagnosticable only with tester
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 its 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 oper-ated.
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.
It will not help if there is a dry joint, this one must be located and fixed with a soldering gun
For Disco 2 its an even freakyer thing named BCU, this one is diagnosticable only with tester
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sierrafery
Well-Known Member
Great, worth a try if it isn't a relay.
Stupid question, but the disco has a lot of yellow relay switches - are these all the same i.e interchangable?
Mclovin, sorry for jumping in on your thread
Yes .....U can see they have the same code (i.e. R6L5, Siemens Y*****)
and how ill i know what is at fault off that diagnostics?? if only it was something as straight forward as a bloody fuse or relay!!! i cant stand cars sometimes!!!!!!
rob away mate as long as its helping you at least it will be benefitting one of us ey!!! haha thanks for the info
rob away mate as long as its helping you at least it will be benefitting one of us ey!!! haha thanks for the info
sierrafery
Well-Known Member
This procedure helps u to see if the MFU is getting inputs, at stage 4 u operate each switch.... if the MFU is getting the input it will beep twice...... (i.e u operate the washer and the MFU doesnt beep it means it didnt get the input from the switch).....after that on stage 6 will check outputs, u must sharpen your hearing and listen the relays.... if they get output from the MFU they'll at least click if the related device wont work..(ie the indicators will not flash but u can hear the relay clicking...then u'll know that the problem is along the wires untill the bulb)............or nothing(or just part) of these things will happen
.........=>u're unlucky ....the MFU is fecked and u must replace it.....Part nr. AMR1280
Yes I know this is a way old thread, and so are 200TDi Discos
Did the answer to this problem every get found I wonder?
Got a very similar sounding issue with my 93 200TDi, the flashers dont work neither do the hazards (though weirdly the hazard switch does still dutifully light up red?!) - but when locking or unlocking the vehicle via fob all the indicators flash once (or three times depending on whether locking or unlocking) so I know all the bulbs and wiring must be sound...
