IVA Rear Fog Light Rules

[Steve_D]

IVA rules require that a rear fog light must only operate when the headlights are on dip or main beam.

A recent IVA rule change now requires that when the headlights are turned off the fog lights shall not come on again unless re-selected. (You can fit a warning buzzer but I’m not interested in that option).

I have a circuit that will work and only requires the use of a bog standard relay and a momentary switch/button for fog lights.

Its only drawback is that if you decide you no longer require fog lights the only way to switch them off is to switch the headlights off and on again. Not a major issue I feel but does anyone have a better circuit?

Steve

[Dave Brookes]

Hi Steve.
Ignore the new rule, it has been scrapped....Sort of.

It is to do with modern production cars that run Can bus systems.

The rules for kit cars are as they were:-
Must only be able to come on with headlights (Dip or main)
Must have a warning light with symbol.

There has been a bit of bother over it to say the least.
All test stations have been informed via email, but it hasn't gone in the "Bible" yet.

[Steve_D]

Thanks Dave.
Was just about to dive back under the dash of a car to fix this.

Would still like the electric wizards to ponder the problem as I doubt this will go away for too long as the 'fog light left on' problem seems to be on the increase.

Steve

[GarethGTR]

I am mid IVA now, and am told that it must be there.

i.e. Fog Lights must ONLY come on when selected. If lights are turned off and then the fog light state must be reset.

Gareth

[AcC8braman]

Just had my IVA they did not test if the fogs come back on after switching the ignition back on

[Steve_D]

GarethGTR said:

I am mid IVA now, and am told that it must be there.

i.e. Fog Lights must ONLY come on when selected. If lights are turned off and then the fog light state must be reset.

Gareth

Sounds like now is the time to challenge it with your test station.
If they stick by the ruling in the book then I have a circuit you can use.

Steve

[PaulKemp]

I would think a momentary switch and locking relay would do the job

[Sloan85]

I have a spare cartek fog control unit. Yours for £15 if interested.

[330p4]

Car builder are selling them now a new product
Ian

[Dave Brookes]

GarethGTR said:

I am mid IVA now, and am told that it must be there.

i.e. Fog Lights must ONLY come on when selected. If lights are turned off and then the fog light state must be reset.

Gareth

Your tester has not read his emails.
As Steve says "Challenge" them over it and you'll be fine

[Steve_D]

PaulKemp said:

I would think a momentary switch and locking relay would do the job

A latching relay only unlatches with the next push of the button. You need something that unlatches when the headlights are turned off.

CBS have a unit but £30 is a little steep.

I have a circuit for one standard relay but if you want the fogs off during a journey you need to turn the headlights off and on again.
I have another circuit using 3 relays but have not tried it yet but you can turn it on and off from the button.

Steve

[Fastpedeller]

I seem to recall that some cars with a rotary switch use a mechanical switch to turn on the fog lights (push the whole button), so that when the heads are turned off the fog is also turned off.

[Steve_D]

Fastpedeller said:

I seem to recall that some cars with a rotary switch use a mechanical switch to turn on the fog lights (push the whole button), so that when the heads are turned off the fog is also turned off.

Yes many cars have this mechanical self cancelling feature in the stalk but lots of kitcars do not use stalk controls hence the original request for an electrical solution.

Steve

[Coskev]

Some use dash mounted light switches that do this,my VRS does.

Electrical solution is buy the Cartec control relay!

[rdodger]

I had my IVA just after this was introduced. The inspector told me nothing had changed if the fog came on with dipped or main beam.

If it came on with side lights then you needed it to go off with the lights or have a buzzer.

[Snake the Sniper]

Would it not be easier to just feed a fog light switch from the out side of the dipped beam switch and then on to a normal relay? I might just be being thick, but I'm not sure I see the problem here.....

[Steve_D]

Snake the Sniper said:

Would it not be easier to just feed a fog light switch from the out side of the dipped beam switch and then on to a normal relay? I might just be being thick, but I'm not sure I see the problem here.....

In your example the fog light would come on again when you next switched the headlights on which (according to the current issue IVA manual) is not allowed. The fog light must revert too, and stay in, the off condition when the headlights are turned off.

Steve

[Snake the Sniper]

Steve_D said:

In your example the fog light would come on again when you next switched the headlights on which (according to the current issue IVA manual) is not allowed. The fog light must revert too, and stay in, the off condition when the headlights are turned off.

Steve

Ah, I see. Mmmm, it's not as simple as it first appears is it?

[GarethGTR]

Hi

Not a problem for me

Being an ECU designer, I designed my own BCM (Body Control Module) so a quick software update and it was sorted.
FYI: the BCM is a great piece of kit - all switches via low current wire to the BCM, all lights etc also wire to the BCM.
You can choose which switches power it up and what the power up does (Hazzard / Main Key switch etc etc), makes for a real simple wiring job....just open the software on a PC and choose what does what and when.
Also, when powered off, draws no current, oh and each switch backlight is programmable for ON/OFF brightness during lights ON and Lights off.... sorts out having to have separate LEDs / warning lights. For example - IVA switch flashes slowly if hand brake is on, fast if ECU has a MIL and stays on if brake fluid is low

Great for fixing problems like the fog light switch etc. and no fuses or relays - just program each output to a current limit.

Not a punt because I am not producing them! not for sale....just saying what I did....

Gareth

[Stuart Mills]

Please allow me to clarify. As with all the IVA rules, it is important to read ALL of the text.
Rule 28 reads;
4. The rear fog lamp(s) must only illuminate when dipped beam, main beam or front
fog lamps are lit (See Notes 3 & 4)
Notes 3&4 read;
Note 3
: front fog lamps MAY be illuminated with the side
lamps only.

Note 4:
Either of the following applies:
1) The rear fog lamp(s) MAY continue to operate until the
position lamps are switched off, and the rear fog lamp(s)
must then remain off until deliberately switched on again or,
2) An audible warning, additional to the mandatory tell-tale
light, must be activated if the ignition is switched off or the
ignition key is withdrawn and the driver's door is opened,
whether the lamps in (RS4) are on or off, whilst the rear fog
lamp switch is in the "on" position.
Please note I have changed "may" to caps in the above.

The FOG should therefore only come on with headlights if you wish to make your life easy.