Rewired Fogs to run without headlights on

AZ-CX9

Member
:
'08 CX-9 GT AWD White
If anyone is interested in a simple way (based on your wiring skills of course) to do this here goes:

(May have to have heated seats for this..)

On small (4 relay) box in very front of engine compartment above fans.
Open top of box, detach from front, and remove bottom cover. Of the four relays, the two SMALLER ones are: fogs (right one viewed from front) and heated seats (2nd from left viewed from front). The pink wire on the SEAT relay provides ignition power (what you want) the green w/red wire on the Fogs relay provides switched power from the headlight relay ( Hate that!). I cut the green wire far enough back that I could splice into the pink wire. Be sure to insulate the left over stub from the green wire. Now the fog relay is "hot" when ignition is on instead of when headlights are on. Done.

(If you don't have the pink wire due to no heated seats..all you need to do is get and ignition source wire to this relay instead)

Now your fogs will come on with ignition and still function on/off from the stock switch (which provides the relay ground thus eliminating the need for an add-on switch)

Cheers.

Andy
 

l-miwa

Member
:
Mazda CX-9
Excellent mod! Following the very simple instructions provided above, it took me less than 30 minutes to complete this.

My fog lights are now useful instead of just decoration. Why manufacturers insist on switching the foglights with the headlights is just beyond me. They really should be switched by the marker lights.
 

jeg0024

Banned
:
2002 22V Protege DX
Why manufacturers insist on switching the foglights with the headlights is just beyond me. They really should be switched by the marker lights.

Who drives with just their running lights and fog lights on anyways? Honestly they aren't bright enough to be anything other than cosmetic anyways. They shouldn't be switched on by the running lights or the headlights, they should be totally optional to have on or off whenever you want as long as at least your running lights are on(required by law). Nice write up tho, it is nice to have control over your fogs even if they are just cosmetic.
 
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l-miwa

Member
:
Mazda CX-9
Who drives with just their running lights and fog lights on anyways?

If you are actually DRIVING IN FOG, then you want ONLY your running lights and fog lights on. And having upgraded them to high power xenon bulbs, they are actually relatively bright.

The point of fog lights is that they are mounted low with a sharp cutoff on the top to prevent the light reflecting back off of the fog into your eyes. This is EXACTLY why you don't want the regular headlights (or even worse, the high lights) on in heavy fog.

If fog lights have become purely cosmetic, then by all means, switch them on / off with the headlights. If however, they are actually supposed to be usable as fog lights, then they should be either switched by the ignition or by the running lights.
 

BoostedSpd6

Member
Contributor
:
MazdaSpeed 6
would this work on the speed 6 cuz we have heated seats also.. just wondering if the relay's were in same location
 

AZ-CX9

Member
:
'08 CX-9 GT AWD White
Just an observation or three...

With the low wide beam of the fogs they are, in fact, very usefull in fog, dust and even heavy rain, especially with the intense light from the HIDs which can actually reduce visibiliy in the above situations by having light scatered back at the driver. However if switched by the headlights and thus only on with the HIDs they DO provide only cosmetic value. By being able to run them alone they THEN become more then cosmetic. I replaced the bulbs with yellow ION increasing their effectivness for fog etc..Though even the stock lights will be better then the HIDs due, again, to the low wide beam pattern. Additionally this is not a bad way to get DRL function...

Cheers and thanks for the kudos!

Andy
 

jeg0024

Banned
:
2002 22V Protege DX
Is it even legal to drive at night with just the running lights and fogs? I see your point but I just dont see anyone really doing it, I mean my car is low enough that my low beams shine under the fog and my fogs just point straight down at the road until I find the time to adjust them.
 

l-miwa

Member
:
Mazda CX-9
...Additionally this is not a bad way to get DRL function...

I was hoping the same thing, but the sharp cutoff prevents them from appearing very bright to other drivers. I think that's why most manufacturers use the high beams at reduced power. Plus, running the fog lights a full power all the time will mean regularly replacing burnt out bulbs.
 

rc51

Member
If anyone is interested in a simple way (based on your wiring skills of course) to do this here goes:

(May have to have heated seats for this..)

On small (4 relay) box in very front of engine compartment above fans.
Open top of box, detach from front, and remove bottom cover. Of the four relays, the two SMALLER ones are: fogs (right one viewed from front) and heated seats (2nd from left viewed from front). The pink wire on the SEAT relay provides ignition power (what you want) the green w/red wire on the Fogs relay provides switched power from the headlight relay ( Hate that!). I cut the green wire far enough back that I could splice into the pink wire. Be sure to insulate the left over stub from the green wire. Now the fog relay is "hot" when ignition is on instead of when headlights are on. Done.

(If you don't have the pink wire due to no heated seats..all you need to do is get and ignition source wire to this relay instead)

Now your fogs will come on with ignition and still function on/off from the stock switch (which provides the relay ground thus eliminating the need for an add-on switch)

Cheers.

Andy


Excellent write up, Andy. I went to do this yesterday and made a modification...
One thing to remember is that this wiring scheme will require you to turn off the Fog light switch when you don't wnt them on (i.e. the daytime). Instead of tapping the heated seat lead, you should tap a parking light lead so that the fogs come on w/ the parking lights (this is the 'look' that everyone likes since the beginning of time). I ran a wire from the rely box to the drivers side headlamp unit. There's a connector (for the constant parking light) there just above the bulb socket (turn signal). The connector has a black and a yellow wire- tap the yellow and now you'll have the fog lamps controllable when the parking lights are on.
 

ux149

Member
The current fog lamps are 51 watts. If I crosswire the fog lamps to the heated seats, how high a wattage can I use for a whiter bulb?
 
:
2007 GT FWD, Bose/NAV
I'm kinda confused by this thread. My foglights work in tandem with my headlights. They only switch off with the hi-beams. This is done purposefully according to law. If the mod is to keep the foglights on with the hi-beams I get it.
 

tidriver

Member
:
Mazda CX-9 GT AWD
qualify as daytime running lights?

since my insurance co gives discounts to cars with daytime running lights, I wonder if this "mod" to run fulltime will qualify.
 

l-miwa

Member
:
Mazda CX-9
The current fog lamps are 51 watts. If I crosswire the fog lamps to the heated seats, how high a wattage can I use for a whiter bulb?

The current relay / fuse rating is 90w for each fog lamp. I have had no problem using the 80w Vision X 4300K bulbs.

I also use the 100w Vision X 4300K high beam bulbs as well. The relay / fuse rating for them is 120w.
 

ux149

Member
I'm kinda confused by this thread. My foglights work in tandem with my headlights. They only switch off with the hi-beams. This is done purposefully according to law. If the mod is to keep the foglights on with the hi-beams I get it.
Hot wiring the fogs is not a perfect solution for the lack of daytime running lights, but it is currently the least expensive and simplest solution. Fog lights with high beams would be kinda useless.
 

ux149

Member
The current relay / fuse rating is 90w for each fog lamp. I have had no problem using the 80w Vision X 4300K bulbs.

I also use the 100w Vision X 4300K high beam bulbs as well. The relay / fuse rating for them is 120w.
Thanks l-miwa. I wonder if the 80watts will overload the heated seats if I crosswire for faux DRL?
 

bill42

Member
:
CX-9 GT
since my insurance co gives discounts to cars with daytime running lights, I wonder if this "mod" to run fulltime will qualify.


Indeed it will qualify. I insured my car from the start knowing that I will be doing this mod. I personally do not want all the parking lights on during the day, as someone else stated. That would put unnecessary wear and tear on all those bulbs. I can't believe that Mazdas don't just come with DRLs like all the cars i have owned since 2000... A nice trick set-up would be to install sone kind of 3 pole relay switch so that when you turn ON the parking lights or headlights, these "fog" DRLs switch off. This is how proper DRLs work like the ones on my 3-series, and it prolongs the bulb life. However, since I don't remember much of my electronics schooling, I think I'll just hook it straight into the switched 12 volts. These bulbs can't be that expensive to replace...
 

l-miwa

Member
:
Mazda CX-9
Thanks l-miwa. I wonder if the 80watts will overload the heated seats if I crosswire for faux DRL?

No potential overload problem. The heated seats circuit is only used to trick the relay into thinking that the "headlights are on". The power for the fog lights still comes through the fog light fuse.
 

ux149

Member
No potential overload problem. The heated seats circuit is only used to trick the relay into thinking that the "headlights are on". The power for the fog lights still comes through the fog light fuse.
Thanks again. You're a wealth of information!
 
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2007 GT FWD, Bose/NAV
So they are hotwired for daytime running lights? Why do that when you just turn the headlight switch to on and you have lights in the day. My 2007 GT has full time lights and autolights. I must be missing something!