Front Fog Lights on with Main Beam

[benharris]

I know that front fog lights can be bit of a contentious issue, and I'm firmly in the camp that dislikes people that drive around with them on, purely for looks.

However, whilst I know it's certainly possible, my question is - would it be legal (i.e. still comply with the vehicle lighting regulations) if I were to wire my front fog lights so that they came on with main beam?

My reason for asking is that although my headlights are aligned correctly (I've checked!) and I have decent bulbs (Osram Nightbreakers), I tend to find that when I have main beam on, I lose quite a bit of the illuminated area directly in front of the car. Living in the countryside with lots of twisty national speed limit roads around means that I end up using main beam quite a bit (obviously when there is no oncoming traffic), and when experimenting, I've found that a combination of main beam and front fogs gives me considerably better light distribution than main beam alone (obviously turning the fogs off alongside the main beam when encountering other drivers).

I've been considering doing this for a while, but wanted to check beforehand to see if I'm likely to run into any legal issues, or problems come MOT time. From a non-legal/regs perspective, I can't see, they would cause any other drivers a problem, as I obviously wouldn't have main beam (and therefore front fogs) turned on if there were any cars in front of me. The only possible problem I can think of is at MOT time, if the front fogs would upset the beam testing machine when main beam was being tested, although this could be avoided by wiring them through a switch to disable the main beam & fog simultaneous functionality.

Any thoughts? [puts flame-suit on!]

[kambites]

I can't see how, legally speaking, it would be any different than the auxiliary driving lights that my car has mounted down in the front grill.

[Skyedriver]

Thing is, IF they are FOG lights, then you should only be using them in fog and falling snow. In those conditions you wouldn't want high beam on as it would "bounce" back at you from the prevailing weather conditions.
This is where things get confusing because those silly little dazzling lights fitted near the ground are often called driving lamps where as driving lamps should be mounted at least 24" (600mm) above ground.

[RB5Bird]

My Subaru has driving lights fitted, less than 600mm above the ground, and they only come on with main beam. I bought a new set recently and all the stuff on the packaging (PIAA) has drawings/diagrams with the different alignments and spread of light allowed for fog lights vs driving lamps.

Not sure of the legalities of it all, but they are almost certainly different types of bulbs and reflectors and stuff.

[H100S]

OP I have often considered this too however running a company car does not allow for me to do this. Might consider it on the wifes though.

For me this is about lighting up the whole area ahead of me not just the furthest distance.

This mod would require the fog lamp feature still to be independent though.

[Zyp]

My 1999 106 GTi had the fogs come on with the main beam - I say fogs, but they were classed as driving lights even though they were in the same place as fog lights.
These were factory fitted too.

I thought fogs and driving lights only differed in size or beam pattern.

It's also something I've thought about doing with my van - I regularly travel down unlit NSL roads and my main beam is pretty woeful.

[kambites]

Skyedriver said:

This is where things get confusing because those silly little dazzling lights fitted near the ground are often called driving lamps where as driving lamps should be mounted at least 24" (600mm) above ground.

I wasn't aware that the height requirement applied to main beam units, I thought it was dipped beam only. My car certainly has OEM lights mounted in the front grill that come on with main beam which are nowhere near 600mm off the ground.

ETA. Like this, the little round lights:

[Renovation]

I live in the country and I simply turn the fogs on, on the lanes as they are handy for spotting potholes at the side of the road and turn them off when I get to main roads.

They are so low they don't dazzle others so I can't see there's an issue.

There is an issue going from Main + fogs + driving lamps (I know you didn't mention them but I've had them in the past) down to dip beam - you can't see a damn thing !

[TooMany2cvs]

kambites said:

My car certainly has OEM lights mounted in the front grill that come on with main beam which are nowhere near 600mm off the ground.

Driving lights, a very different beam shape to fog lights.



Fogs are a short, wide, flat beam, intended to go "under" the water droplets in the air without bouncing back.
Driving lights are a long, thin, tall beam, intended to light stuff a long way in front of you.

[benharris]

Cheers guys - that's a far more positive response than I was expecting to get, to be honest! I was preparing to be chastised for daring to suggest using fog lights for any circumstance other than zero-visibility fog!

Just to clarify (in case of any confusion), the way I'm planning to implement this means that I'll still be able to use the fog lights with dipped beam when it's foggy, exactly how they are at the moment - I'll simply have an extra switch on the dashboard (where I currently have a convenient 'blank' space at the moment) that will enable the 'main + fogs' function, meaning that when when I switch to main beam, the fogs will also come on (all relay'ed correctly etc).

With my intended wiring change, I'd have the following scenarios available:

[with new fog/main switch turned off] e.g. exactly the same as the car is at the moment.
- parking lights only
- dipped lights only
- main beam only
- dipped lights + fogs (when original fog switch turned on)

[with new fog/main switch turned on]
- parking lights only
- dipped lights only
- main beam + fogs
- dipped lights + fogs (when original fog switch turned on)

RB5Bird - Coincidentally, the car I'm talking about is a classic Impreza too! I had considered the PIAA driving light kit, but the lights look like they don't sit as flush in the bumper, which I wasn't as keen on, plus don't the driving lights project further, than covering the up-close area - or do they do a good job of covering both?

H100S - My planned modification will still enable the fogs to work independently (with the dipped beam), exactly as they do currently.

Reonvation - That's exactly the kind of thing I'm referring to - it's if an animal runs out or something like that, that the fogs will add their benefit. I just want to automate it, so it'll I only have to toggle main beam on/off and not have to also fumble for an extra switch each time too.

Edited by benharris on Monday 10th November 22:32

[roverspeed]

I wired my transporter fog lights to do this, cars fitted with h4 headlights lose short range when on main beam. Anyways I had the fogs and additional 4 driving lamps wired to the main beams via relay. No problems at mot time, they didn't even mention it. They never asked to switch the fogs on separately

[Flibble]

According to the RVLR if you have them on the main beam switch you can probably treat them as an extra pair of main beams, though I'm not sure how that plays into retaining the switch for using them as fog lights.

From: http://www.legislation.gov.uk/uksi/1989/1796/sched...

RVLR said:

Requirements relating to optional main-beam headlamps

Any number may be fitted and the only requirements prescribed by these Regulations in respect of any which are fitted are those specified in paragraphs 7, 10 and 12(a) of Part I and, in the case of a motor vehicle first used on or after 1st April 1991, paragraph 5 of Part I.

Paragraph 7 says they must be white or yellow.
Paragraph 10 says that main beams must be on a switch that switches between main and dipped beams, and that matched pairs have to operate together on a single switch.
Paragraph 12(a) says you must be able to adjust the beam direction while stationary (this is also a requirement for fog lights, so covered).
Paragraph 5 says they must have a BS mask.

There is no requirement for being a minimum distance above the road, or indeed any other positional requirement (other than not shining backwards).

The only slight problem would be that for paragraph 10 to be satisfied you'd probably not be able to have a separate fog light switch.

[benharris]

Thanks for that. I did go looking for the regs, but couldn't find the specific bit that was relevant.

I wonder if by having the "mode" switch, it would technically still be considered to be within the regs, because depending on which mode they were in, they could be either driving lights, or fog lights. They would always be either one or the other and couldn't be both at the same time - meaning that they would satisfying the regs for whichever mode I had selected at the time!

Sounds like a (reasonable?) argument to me, anyway! :-)

[RB5Bird]

They just light up everything. Really good, but are more directed, so less of a "spread".