rear fogs 300tdi

The control unit is the MFU multi function unit which 300 series discos have always had positioned on the rear of the fuse board although from 97-98MY it interfaced with the rear foglamps.

There's only two relays on the fuse board that's indicators and heated rear screen the rear foglamp relay is located behind the passenger kick panel.

I could well be wrong but just double checked on Rave in the 1997 edition of the electrical troubleshooting manual and the rear fog lamp relay on both manual and autos is with the bank of relays under the glove box.

thanks so much guys,the relay i was checking was under glove box next to the green box,which i guess is the MFU,ill get back to you when i go check it,really appreciate the help lads...

DAZ

rabbiter said:

thanks so much guys,the relay i was checking was under glove box next to the green box,which i guess is the MFU,ill get back to you when i go check it,really appreciate the help lads...

DAZ

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The MFU is on the driver's side by the fuse box. The ECUs on the passenger side, by the relays, behind the glove box, are for the electric windows and central locking / immobiliser...not that it makes any difference to your fog lamp problems

Richard Martin said:

The MFU is on the driver's side by the fuse box. The ECUs on the passenger side, by the relays, behind the glove box, are for the electric windows and central locking / immobiliser...not that it makes any difference to your fog lamp problems

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exactly :doh:

DAZ

ive checked and found the loom with the colours given and there wasnt even a relay attached,ive bought one and put it on and still nothing,the tell tale on the switch doesnt come on,so i assume ive bought the wrong relay or the switch is broken,is it a specific relay i need, the one i bought was described on the box as a switching relay!
it did have the numbers 30,85,86,87...as you can probably tell,i know nothing about this kind of thing...

DAZ

No it's not a specific relay, the relay is just a standard 4 terminal relay that is common to other circuits that you may have in your disco, so without checking the numbers I would say you have the correct one.

thanks discool,so it must be the switch??

rabbiter said:

thanks discool,so it must be the switch??

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Well may be, but how oftern are the switches used not a lot I'd check the supply to it first although there s/h switches on eBay

Question: do you have any problems with the wiper or interior light delays, lights ON beeper as that is an indication of a faulty MFU along with rear fogs not working... as I found out

Right mate you need a circuit tester or a multi meter.
There wont be a live at the switch for the lights as it earth switches the MFU (bearing in mind I'm going on 1997 spec, although yours is a 1997 registered vehicle it does not guarantee it's a 1997 spec vehicle).

At relay pin 86 blue and red wire and also at pin 87 which should be the same colour there should be a permanent live, check this first and let me know.

discool said:

Well may be, but how oftern are the switches used not a lot I'd check the supply to it first although there s/h switches on eBay

Question: do you have any problems with the wiper or interior light delays, lights ON beeper as that is an indication of a faulty MFU along with rear fogs not working... as I found out

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i did have a problem with the light delays and bleeper,but found that to be a loose connection on the button on the door pillar,thats now sorted,thanks mate...

DAZ

well after stchris356 offered his advice over the phone,we"ve pretty much got it down to a faulty switch,so going to get one and hopefully job sorted,so a massive thanks to chris and everyone else who offered their advice to me...

DAZ

well,i got the new switch,put it in,and nothing,no tell tale,no fogs,what now lads,this is giving me a headache...

DAZ