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MG MGF Technical - Front & Rear Fog Lights

The problem:

To have both front and rear fog lights on with side lights but no dipped haedlights.

The point of front fog lights is to look under the fog and avoid the glare from the for that you get with dipped headlights (or main beam for that matter),

You can have you front fogs on on the f with only side lights on (if you have had them fitted as an extra)

But the rear fog lights (standard fitment) only come on with dipped head lights.

After looking at Dieter's excellent web page of wiring diagrams I am considering wiring a feed from the front fog light switch via a diode to the Blue and black cable from fuse 11 to the fog light relay unit. The blue and black wire would also have to be cut just before the relay and a diode inserted to avoid back feeds.

Is this possible?

I have not looked yet, but dose anyone know where the fog light relay is?

I have had great theories like this before, but have than found what I was expecting to be a wire is a link which is part of the fuses box, is this the case on the f?

I use the term relay loosely when refering to the fog light relay as it is more then a relya. The diagram suggests that it is a relay, but the switch is only a push switch with one press latcching it to on, and a second press latching it off. It also goes off when the ignigtion is switched off or when the dipped beam is switched off and will not come on until dipped beam and ignition are back on again and the switch is again pressed, so logic control must also exist in the "relay".

BTW the above is require for correct use of front fog lights and rear fog lights for use in fog, posers, hairdressers and the like will not understand this aas they are lost as to the strange name given to those little roud lights on the front of their car which are used to distinguish it from other lesser motors on the road (sad isn't it) still mommy won't allow them out in bad weather anyway! :))



Andrew

Just a few words to the fog guard lamps 'from the memory' ;)

Rear fog guard lamps are incorporated into the tail lamp units. A warning lamp in the
instrument cluster illuminates when the rear fog guard lamps are on. Operation is controlled
by a switch on the centre console and the multi function ECU. For the rear fog guard lamps
to operate the headlamps must be on and the ignition switch must be in position II. Rear fog
guard lamps operation is automatically cancelled at ignition off.

Power supplies
Fusible link 1 in the under bonnet fuse box supplies a permanent feed to the
headlamp lighting switch on a brown wire.
Fusible link 4 in the under bonnet fuse box supplies a permanent feed to the ignition
switch on a brown-pink wire. When the ignition switch is in position II, the feed is connected
to fuse 1 in the passenger compartment fuse box on a black yellow wire. Fuse 1 supplies the feed to the coil of a fog lamp relay in the multi function ECU on a green wire.


When the headlamps are on, a feed from the lighting switch is connected to fuses
9 and 11 of the passenger compartment fuse box on blue-pink wires. Fuse 9
feeds the switch contacts of the fog lamp relay in the multi function ECU on a blue-red
wire. Fuse 11 supplies a feed to a switch in the multi function ECU on a
blue-black wire. Pressing the rear fog guard lamp switch temporarily earths the switch in the multi
function ECU by connecting the red-yellow wire, between the multi function ECU and the
rear fog guard lamp switch , to the Black wire between the rear fog guard lamp switch
and an earth point. The switch closes and earths the coil of the fog lamp relay on the Black wire between the multi function ECU and an earth header. The fog lamp relay energises and connects the supply, from fuse 9
in the passenger compartment fuse box, to the blue-yellow wires between the multi function ECU
and the:
- LH and LH rear fog guard lamp; the lamp is earthed by a Black wire connected to an earth header and illuminates.
- Rear fog guard warning lamp in the instrument pack; the warning lamp is earthed by a Black wire connected to an earth point via the passenger compartment fuse box and illuminates.
- Tell tale LED in the rear fog guard lamp switch; the LED is earthed by a Black wire connected to an earth point via the passenger compartment fuse box and illuminates.

Turning the ignition switch off, or pressing the rear fog guard lamp switch again, de-energises
the fog lamps relay and extinguishes the rear fog guard lamps. Turning the
lighting switch to side lamps or off extinguishes the rear fog guard lamps but, while the
ignition switch remains in position II, the fog lamp relay remains energised. If the lighting
switch is subsequently turned back to the headlamps position, the rear fog guard lamps
illuminate again.

12V/21W GLB 382 is hopefully the right No.
To answer your question.
I assume the relay is lcated inside the MFU, but can be wrong.
http//:www.lame-delegation.de/MFU/index.htm
Dieter Koennecke

Rear fog lamp relay is in MultiFunction unit near under dash fuses (as Dieter says). Not sure on front fog lamp relay but try up under dash on drivers side against wing. There are several places for individual relays there. They are well hidden.

Bruce
Bruce Caldwell

This thread was discussed between 27/12/2001 and 01/01/2002

MG MGF Technical index

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