does anyone know what fuse/relay controls the ignition warning and lights on warning buzzer also my 2 of my rear lights have gone out but opposite ones top right bottom left everything else is working front lights (side/main and full) and all interior toys are working fine
thank you
1998 300tdi

come on someone must know

please

Hi,

There's a multifunction unit mounted on the back of the fuse board below the steering wheel, the buzzer is located in there.
The unit controls things like intermitant wiper delay, interior light fade, rear wiper, etc. I don't know there are any fuses for that circuit, unfortunatley the unit is pretty much non repairable (i'm from an electronics background and I couldn't be bothered), if you do need to replace it I think they are about £97.00...

There is a test mode as described on the rave cd:
(same year as yours so should work)

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 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.


Hope this is of some help, if you need it I can send you a copy of the cd so you can trace the wiring diagrams.

PS. After two days trying to fix my rear wiper that had a fault, I was sure it was the multifunction unit not giving an ouput to that circuit, turned out to be a stuck relay... Don't overlook the obvious.

Cheers for the reply mate
after alot off fannying on i discovered a blown bulb in the bumper(obvious i know)
and a possible faulty earth on my rear side light now repaired
i did the full diagnostic and all worked fine all beeped and came on when they should
but still i have no buzzer for the key/lights on warning and i am deffinate it was there before ?

S368 VOP you are a bloody life saver.
I have been tearing my hair out for two weeks with a similar problem to our friend here.
I replaced the MFU which cured all except the rear wiper.
I have replaced almost all the wiper bits incl a new motor, switch relay etc and all to no avail.
Just run your diagnostic programme twice and on the second run it all worked fine.
Thanks very much for the info.

S368 VOP said:

Hi,

PS. After two days trying to fix my rear wiper that had a fault, I was sure it was the multifunction unit not giving an ouput to that circuit, turned out to be a stuck relay... Don't overlook the obvious.

Click to expand...

where was it??? my rear wiper doesn't work that often so i think it could be that at fault..... where abouts are they?

jax13 said:

where was it??? my rear wiper doesn't work that often so i think it could be that at fault..... where abouts are they?

Click to expand...

If yu dont know where the rear wiper is - how do you know it aint working?

I normally find the rea wiper is inside the n/s rear brake drum

Rear wiper relay is located somewhere in the passenger footwell, I can check exact location on rave cd if you need.

Jon.

It's the green one behind the side panel in the passenger footwell on my 97.

make sure the buzzer itslef is not faulty. easy to enough to check. then get a replacement from maplins etc... bit of solder and save yourself 100 squid.