Rear Foglamp (IVA)

[Joseph.Ryan1]

My rear foglight and warning switch is powered from the sidelight circuit.

NO. This is not acceptable with the IVA people.

The rear foglight and warning switch must illuminate in conjunction with the DIPPED and MAIN Beams only.

Any help or suggestions as to how I can achieve this would be very greatly appreciated.

The wiring harness I have used is a Trust Electrical supplied by YKC. The dipped and main beams are two separate circuits supplied through two relays.

[Dane_Rescueman]

Re: Rear Foglamp (IVA)

Its all a bit hazy to me. My eurobox will only allow rear or front fog lamps when dipped headlights are selected. Full beam or sidelights only cuts the fogs off. My Mitsubishi allows the fog lights on with side or heads. My Berlinetta with standatd Cortina lighting electrics only allows the rear fog light with dipped beam. I cannot find out from my IVA notes what the required wiring is, just that it must have a tell tale! Good luck with it!

[Peterx]

Re: Rear Foglamp (IVA)

I don't know that loom but you need to take the supply feed for the Fog light(and warning light) from the main headlight switch so that the fog light can be only be illuminated when either the dipped or main beams are on.

[chris_cussen]

Re: Rear Foglamp (IVA)

If the wiring is similar to some of the Sierras then you have a permanent live feed to the relays, and the switch is in the earth circuit. This makes switching the foglight a bit more tricky to say the least. The picture should show you what you need to do. The extra wires you will have to add are in green and you will also need an extra relay.

[Dane_Rescueman]

Re: Rear Foglamp (IVA)

Chris, My wiring diagram for the Sierra series shows that they all had a rear fog light. I'll look it up and find how/where they took the feed from. It would have to originate from the lighting switch/relay.

[Dane_Rescueman]

Re: Rear Foglamp (IVA)

I,ve had a look and my diagram shows the feed for the rear fog light switch comes from the sidelights pin of the main lighting switch on a post 1987 car! So, it appears that the Sierra would fail IVA !!!!!

[Dane_Rescueman]

Re: Rear Foglamp (IVA)

Pre 1987 the power seems to come via the dipped beam fuse to the fog relay then the rear fog switch direct to the lights. It looks as if the rear fogs would extinguish when on main beam! You are all correct. It is a minefield!

[chris_cussen]

Re: Rear Foglamp (IVA)

The diagram was the arrangement I ended up using. I've a cabrio with Sierra switch-gear (which included the make-to-earth light switch) and a Premier Wiring loom.
Initially I had the fog-light from the switched live (ignition) until I realised it would fail IVA, and came up with that solution.

There is whole number of things a Sierra would fail IVA on!

[stevejgreen]

Re: Rear Foglamp (IVA)

As the Fog lamp should come on with Dip or Main beams, how about a couple of 1N5400 diodes from each circuit feeding a switch for a small relay.
Heavier duty Diodes could be used and then there would be no need for a relay but take care that the additional load can be carried by the Dip and Main wiring
Diodes can be neatly sleeved with heatshrink for insulating the solder connections.

[Joseph.Ryan1]

Re: Rear Foglamp (IVA)

Thanks for the help re Rear Foglamp (IVA). Will let you know the outcome and result of IVA re-test.

[cameronfurnival]

Re: Rear Foglamp (IVA)

just to add to this - having wired it up just now...circuit diagram attached.

I found I had problems because the brown/yellow and brown/white were reversed on my column switch! Once found and checked everything is ok. The fog lamp can only come on when the main or dip is on. Of course, this is ford wiring with everything switched earth.

Hope this helps someone....
foglampcct.jpg

The bottom light switch is the switch which controls sidelights then clicks further to turn on either main or dipped. The switch above it is the main/dip flasher switch. Its into that link between the two that you need to connect the fog lamp switch. Its a brown/black wire. I think I have drawn it with three outputs but it canonly be two - main or dip.

No need for the dip/dim set up that some fords had and no need for daytime running lights for the IVA at the moment.

[b_caswell]

Re: Rear Foglamp (IVA)

Why do they switch on the earth return seems back to front to me.

[Dane_Rescueman]

Re: Rear Foglamp (IVA)

My loom is a cortina Mk III - the lights have their own separate relay and fuse pack. The lighting switch earths a powered relay which then energises the dipped beam. Its so daft that I spent hours trying to find out why I couldn't select main beam until I found that the coil of the main beam relay needs the main beam warning light in circuit. The bulb had blown thus the main beam changeover relay wouldn't latch. AAAArgh! I feel yet another re-wire/wiring change coming on.