Just connected my battery last night and tested everything.

My rear fog works but when you put main beam on (not flash) the filaments in the bulbs up front change over to main and the dip goes off (correct) but the fog light switch gets its power from the dip beam feed, so in effect if you have the rear fog on and put the main beam on, the fog will go off.

This is correct to the sierra diagrams (stalks with square hazard - horn push on steering wheel) but just wondered if this is ok for iva etc.

Does everyone elses do this (using the same stalks)?

Cheers
Stott

Should be ok.

But if you wanted it to work when the main beam was on as well then you could take the power from the sidelight feed rather than the dipped beam feed?

Doesn't sound correct to me.

Davie

IVA asks it to work with Dip, Main, or Front Fog. The wording isn't great, but is means with all of those, not just with one of them.

they need to work with all front lamps. (fog, dipped and full beam) the reasoning behind this is if they turn off when there is full beam on, then the talltale goes off as well. so you may be unaware they are in the "active" position. once you flic your full beam off your fogs will re-activate and could cause the driver behind some confusion.

Rear fogs used to commonly work only with dipped headlights. More recently they work with both dip and main and thats now required for IVA I believe (wasn't for SVA).

adrian

Yeah for the IVA your rear fog can only come on when dipped and main are active, but not when just the sidelights are on.

Easiest way is to use the switched earth off the Sierra column stalks to a standard relay. Took me 25 mins to sort it.

[Edited on 14/5/10 by deezee]

No probs I'll sort it now, it is correct at the moment, (exactly how the sierra was) Just wanted to know if it was iva ok which I now know it isn't, cheers

Stott

I'm not sure what the IVA book says but front fogs are only effective with dipped beam. They are set low on the car with a low beam to shine UNDER the fog (or as low as possible) so that they don't simply bounce back off the fog and dazzle the driver. Dip beam also acheives this to a lesser extent so also does not dazzle the driver. But full beam causes huge dazzle (white out in heavy fog) so should not be used with front fogs. Consequently fogs should be wired to switch off when main beam comes on. That is the reality of the use of fogs and main beam and the IVA book should reflect that (if you excuse the pun) but I'm not sure if they do!

Yeah I know what you mean, that's why in my mind it should be fine, it's the rear fog we are on about btw.

You don't put mains on in fog anyway so what's the issue? vosa eh.........