fog light wiring

[rendoll911]

I bought my Ti used and it had foglights but it didnt have any switch to turn them on and off, so i figured they were an add on. They turn on as soon as i turn the car on and they stay on with the parking lights on, but as soon as a turn the headlights on they turn off. Anyone know how to keep them on with the headlights on? Maybe wire them to stay on 24/7 or would that cause a heat problem? Currently both of my foglights are cracked and for all i know it could be from overheating... so it would kind of be a waste to buy new lenses and have them crack again. Anyone know?

[1996 328ti]

Legally the fogs need to go off if you have your high beams on.
The fogs sit pretty low (as most do) so they get hit with small rocks.
I would think when the lights are on they are subject to the elements a but more.

[rendoll911]

I know about it being illegal to have your fogs and highbeams on but i just want my lowbeams and the fogs to be on at the same time. Also, i heard that dealers would replace the lenses if the they couldnt fit a pencil tip in the crack (supposively that means it was from heat) and they wouldnt replace on warranty if the pencil tip fit in the crack( i guess that would be from debris)

[GDB]

they may have done that when the car was under warranty, but I think we have all fallen out of warrenty. As far as wiring, you might be able to get away with wiring them to your corner lights, that way when the parking lights, or headlights are on then your fogs will come on.

[gooten1]

If you wire them to your corner lights, they'll blink when you use your blinkers.

[GDB]

If you wire them to your corner lights, they'll blink when you use your blinkers.

I didn't think about that little detail.

[rendoll911]

ahah good point

[John Firestone]

At the risk of sounding positive :), I thought the yellow front position lights and the front turn signals used separate 5W and 21W filaments, respectively. If that is true and you tie the front fog light relay to a 5W position light wire or pin, the front fog lights should stay on and not cycle with the turn signals.

[aceyx]

i have a set of 100w driving lights wired up to the corner markers, and they do not blink with the turn signals.

so JF is correct; if you splice into the wire that is predominantly white (i can't remember if the stripe is brown or yellow) then the lights will not blink with the signal or hazard on.

i believe that splicing into the blue wire (since the remaining wire--brown--is ground) that you would have that problem.


most likely the previous owner used wiretaps, so look around your engine bay for little blue plastic things. find out which wires they're connected to and let us know. it may just be that you have to disconnect one.

[rendoll911]

I really dont know anything about wiring so im gonna try to take some pictures of the wiring and maybe one of you electrical geniuses can help me out!

[rendoll911]

corner lamp wires
http://www.iupload.net/102004/IMG_0433.JPG

wires from driver fog light
http://www.iupload.net/102004/IMG_0434.JPG

Driver low beam (outlined black wire is coming from the driver foglight)
http://www.iupload.net/102004/aIMG_0435.JPG

[rendoll911]

Passenger low beam
http://www.iupload.net/102004/IMG_0440.JPG

Orange wire coming from the back of the driver fog to the passenger fog
http://www.iupload.net/102004/IMG_0441.JPG

back of passenger fog
http://www.iupload.net/102004/IMG_0442.JPG

[rendoll911]

black wrapped wires coming from passenger fog
http://www.iupload.net/102004/IMG_0446.JPG

Black wrapped wire gets wrapped with more wire and going behind the battery case
http://www.iupload.net/102004/IMG_0447.JPG


after that i cant track any more of the wires

help me solve my wire mystery! thanks!

[rendoll911]

bumb

[aceyx]

when you turn on the car, if the parking lights on, are the fogs off?

if you open the battery compartment, are there extra wires (other than one -, one +) coming off the terminals? how many? do you have an upgraded stereo system, other than a head unit?

open up the fuse box and look for any non-oem looking relays (boxes that are not orange, seafoam green or matte black). what've you got? there might also be a vagrant relay somewhere in the engine bay.


also, the second wiretap in the pass.fog goes to the yellow wire of the low beam? this is a conundrum, i'm not sure i'll have an answer for you at the end.

[rendoll911]

when i turn the car on the fogs go on, also when i turn the parking lights on the fogs stay on as well, but when i turn on the lowbeams or highbeams the fogs turn off.

There's nothing in the battery compartment and the stereo is stock

fusebox appears to be stock

the 2nd wiretap seems to serve no purpose other than connecting one of the green wires coming out of the wrapped electrical tape to the foglight. The wire tap from the passenger low beam lead into a different much thicker bundle of wires which seems to be stock. I think this tap was just a screw up? Doesnt seem to serve any purpose.

this is what it looks like to me: The black wire from the driver low beam is powering the driver foglight then other wire from the fog light(orange) is connected to the passenger fog light. And i have no idea where the two wires from the passenger fog came from...

should i take this do a professional? If so, where?

[aceyx]

the entire thing looks like a hack job. i'm not sure what was done but it looks like the fog lights are actually taking power from the low beams, but when the lows are turned on, the relay connects the ground for the lows and the power follows the path of least resistance (through shorter factory wiring, bypassing the wiretap) which makes the fog lights turn off.

if that's the case, then the easy solution would be to change the wiretaps from the low to the high beams (fogs would be on with car, on with low, and off with high). but i really don't know if that's the case since i'm stumped about the second wire coming from the passenger fog as well.


does the passenger fog have an original connector (will look like corner marker fitting)? it would somewhat make sense then, that the previous owner simply got the fog lights from salvage, had to rewire the driver's light but left the connector on the passenger, and only wired the ground coming from the passenger fog, without undoing the tape.

would a diagram help? i'm not sure i'm clear.


in any event:

possible solution: change wiretaps going into low beams into high beams. NOTE: may not work.

solution #2: redo the wiring (pretty easy, but time consuming).

[rendoll911]

ill take a picture of the passenger fog

I'm thinking of trying to switch the wire tap to the high beams... Is it difficult and is it reversible?

[rendoll911]

one other thing: could those 2 green wires be from the temperature gauge? because im missing the passenger air duct

[rendoll911]

passenger fog light connections
http://www.iupload.net/102004/IMG_0452.JPG

non-existant brake duct
http://www.iupload.net/102004/IMG_0453.JPG

fuse box
http://www.iupload.net/102004/IMG_0454.JPG

[rendoll911]

haha one more thing... which fuse is the heated mirrors fuse? those dont seem to work

[aceyx]

flip the lid of your fuse box cover. it should be F19 (though you can see which fuses have blown without removing them).

the green wires are for the temp sensor. how has your mileage been? i would think it would be setting off something in the ECU. if not then i would go ahead and try tapping into the high beam.

get some taps and stuff called liquid electrical tape. your hardware store should carry both.
remove fuse for headlights (F23/25/29/30?) tap the black wire from the drivers.fog into the power (non-brown) wire of the high beam. replace fuses, turn on car and test it out.
if it works, remove fuses and tap from low beam and apply liquid tape since you don't want corrosion or a short. replace fuses.

if it doesn't work, and the route that i would personally take is to rewire the entire thing with a relay and replace the temp sensor.


i also just noticed where you were. some of my undergrad friends are up at lake sacondaga for the weekend (one has a cabin there). was gonna go but flights were $$$ i don't have at the moment.

[aceyx]

oh, and i claim no responsibility if you blow yourself up. these are suggestions, since i'm not a mechanic.

it is however, relatively safe.

[rendoll911]

ok i just found something else out when my lights are off and i flash my high beams the fogs stay on.... so this means if i tap into my high beams my fog light will finally work?!?

[rendoll911]

haha dude you should have when to sacondaga you would have helped me with this wiring **** :biggrin:

[aceyx]

it should work. i actually didn't know that the low beam power was hot when the car is on; i thought that the relay would close the power, instead of the ground (which it apparently does). that being the case, i imagine the high beam would be the same.

anyway, good luck with it and let me know how it goes. i don't know how much use i'd be if i were out there, since i'd probably be riding snowmobiles during the day, and drunk at night.

are you a cute chick? maybe i'll come out. :)

[aceyx]

any updates?

also, please excuse my creepy joking tone. i'm not actually serious (about 99% of the time) and on top of that my girlfriend would kill me--if she could ever catch me that is (she gets sport-induced asthma).

okay i'm done.

[John Firestone]

REVISED!
[I looked again at your pictures and realized I had got things interchanged. I have corrected my guess below and how you can check it.]

I finally got a chance to look at the ETMs and try to figure out what is going on with your fog lights. Good grief, what a hack.

From your pictures and description, it appears your fog lights are wired in series like a string of christmas tree lights. :rolleyes: My best guess is that the passenger-side fog light end of the string, the black fog light wire to green wire going into the fusebox, is connected to switched power that is hot in run and start. The driver-side fog light end of the string, the black fog light wire connected to the driver-side low beam, connects to ground through the low beam filament.

I have a few questions to check this.

Are your fog lights a bit dim?

When you unplug the passenger-side fog light, does the driver-side fog light go out?

With the ignition on and the passenger-side fog light unplugged, what voltage do you measure between ground and the black wire going to the passenger-side fog light?

With the passenger-side fog light plugged back in, do both fog lights go out when you unplug the driver-side low-beam?

With the ignition and light switch off, and the driver-side low beam unplugged, what resistance do you measure between ground and the brown wire going to the driver-side low beam?

-John

[robcarync]

wired in series! wow! i actually know the difference between series and paralell due to a physics class! my teacher was right...that information WAS useful!

sorry guys i just got excited for a second...

[rendoll911]

John, Thanks for the update! Right now i am at college so i'm afraid that i wont be able to answer all of your questions, but i will this weekend.

Yes my foglights are very dim.. they suck

And i do know from fooling around with the lights that when one of the foglights was unplugged neither of them worked, but i dont remember which light was unplugged.

Also, thank you so much for everyone who contributed to this thread, it is really appreciated.

ps: aceyx im not a girl but i could wear a wig if you wanted hah

[rendoll911]

the green wires are for the temp sensor. how has your mileage been? i would think it would be setting off something in the ECU.

i just saw this from another thread

That was only on the cars with a cold weather package. And to heat the locks you have to pull up on the door handle while the car is locked, holding it up is what triggers the heater. If you're not sure if you have to cold weather package then look in the passenger side brake duct for a flat, round sensor, if it's there then you have the cold weather package.

i dont have heated seats, so i dont think i have the cold weather package, so do you think that sensor should still be there? My temperature gauge seems to work fine and i have a different sensor in my drivers brake duct. Could that be the temp sensor?

[gooten1]

I don't have the heated seats, but I do have a sensor.... hmm.... and I live in South Carolina...so cold weather consists of anything below 50 degrees Farenheit. d=

[aceyx]

my understanding is that the driver's brake duct is the temp sensor for the OBC, while the passenger sensor is for OBDII (works in conjunction with MAF sensor).

rendoll, no wigs please. i had a bad experience once.

but i suggest undoing all the taps (remember to cover the exposed wire afterwards) and redo it with a relay and some 16g wire. pretty much everywhere carries auto relays, but get a fused hella one if you can.

i can give you a rundown of what needs done.

[GDB]

i just saw this from another thread



i dont have heated seats, so i dont think i have the cold weather package, so do you think that sensor should still be there?

Heated seats have nothing to do with the cold weather package. From my understanding, that sensor is only on cars with the cold weather package. This is second hand knowledge though so I could be wrong about the sensor only being on cars with the cold weather package.

[bimmer95]

The low beam 12v+ wires go to ground when the headlights are off, so the genius that wired up that mess used them as grounds for the foglights. What a hack job. Find someone with a soldering iron (that knows how to use it!), some solder and some heatshrink and fix that mess before you end up with an electrical fire.

[bimmer95]

From your pictures and description, it appears your fog lights are wired in series like a string of christmas tree lights. :rolleyes:
They're not in series, see the T-tap between the green wire and the orange one?
http://www.iupload.net/102004/IMG_0452.JPG

That green wire is obviously going to an ignition switched wire providing 12v+ to both foglights. The other green wire, with the lovely butt connector splice, is wired up to the 12v+ wire on the low beam... providing a poor 12V- source until the headlights are switched on.

[rendoll911]

They're not in series, see the T-tap between the green wire and the orange one?
http://www.iupload.net/102004/IMG_0452.JPG

That green wire is obviously going to an ignition switched wire providing 12v+ to both foglights. The other green wire, with the lovely butt connector splice, is wired up to the 12v+ wire on the low beam... providing a poor 12V- source until the headlights are switched on.


it sounds like this man knows what he is talking about! anyone else agree?

i really wish i learned how to do all this electrical stuff :ashamed:

[aceyx]

here's a diagram:
http://www.hella.com/produktion/HellaPortal/WebSite/Interne_usa/ProductsServices/PDF/Inst_450.pdf

pretty easy like i said before. solder any connection you can (even crimps), and use a bit of silicone on taps (prevent air/water oxidation). clean up the hack job while you're at it -- if the wires are a little green, make sure the battery is disconnected, run a little vinegar&water past it, rub clean, flux and solder.

[John Firestone]

They're not in series, see the T-tap between the green wire and the orange one? That green wire is obviously going to an ignition switched wire providing 12v+ to both foglights. The other green wire, with the lovely butt connector splice, is wired up to the 12v+ wire on the low beam... providing a poor 12V- source until the headlights are switched on.I think it would be foolish to suppose that anything is obvious about the wiring other than it was a hack job. I like your suggestion which would then mean the left foglight connects to ground through the left headlight and the right foglight through the right headlight.

I think it would be a good idea unplug either fuse F11 or F12, then unplug the headlights one at a time to confirm that the nearest foglight and only the nearest foglight goes out. There is no point in needlessly hacking up the car because the installer did something even more silly than we can imagine!

[John Firestone]

here's a diagram:
http://www.hella.com/produktion/HellaPortal/WebSite/Interne_usa/ProductsServices/PDF/Inst_450.pdfThe link redirects me to Hella's home page. Phooey.

[bimmer95]

I think it would be a good idea to unplug the headlights one at a time to confirm that the nearest foglight and only the nearest foglight goes out.
With the way it's wired, unplugging the headlights won't effect the foglights. The most simple test would be to unplug the black wire from the back of the one foglight. If the other foglight stays on, then they're wired up how I mentioned above.

[John Firestone]

With the way it's wired, unplugging the headlights won't effect the foglights. The most simple test would be to unplug the black wire from the back of the one foglight. If the other foglight stays on, then they're wired up how I mentioned above.Good point. The last 3er lighting circuit I wired was the position lighting which is split into two independent circuits, whereas the headlights are joined.

Removing either fuse F11 or F12 and then testing each headlight/foglight pair would work. (I will correct my earlier post.) I myself would try that first (because it is easily reversable) rather than start cutting wires. It might be that the installer actually did something right. :rolleyes:

[aceyx]

craptastic. backed up here:


EDIT: link fixed. sorry folks, i've come down with a small case of the moron today. should be gone by 40.

EDIT(2): link deleted. if you'd like the file, PM me.

[rendoll911]

link no worky