Any ideas on how Fogs are wired (99 with facelift mod done)

[legbuh]

Ok, my 99 A4 has the facelift console done. It has the front and rear fog light buttons (and ESP).

Previous owner said he wired the fog lights to come on with the headlights. Headlights are euros with H7 HIDs and fogs are also HIDs. I saw all 3 ballasts this weekend doing the radiator swap. :) They are also independant of brights.. he showed me the relay I said I could put back if I wanted the fogs to go off with the brights.

So, I thought maybe he had the fog light relay for the facelift and had followed part of the wiring for that.. I pulled the stereo out to take a look and I didn't see anything. :(

When the headlights are turned on, the fog lights go on too, and so does the little light on the foglight console button.

I'd like to actually get the foglights to work independant of the headlights, so I had hoped to find the new foglight module in there, but didn't see anything. I did see some electrical tape over part of the wires going to the button, but after that it was the stock "hockey tape". And the wires were going off down to the driver's side.

Just curious if anyone has any idea how these might have been wired... and how hard it would be to wire the fogs using the light.

Also, rear fogs... never heard of these before.. are they just the reverse lights that should turn on with the rear fog button? I know he said those weren't hooked up. :)

Thanks

[Poopie]

Mawhitey i think posted a work around for people that upgraded to the facelift center console. It's pretty simple. I did it years ago, but I can remember which wires to tie together.

[Mad Cow]

Rear fog light is just the left brake light always on so people behind you can see you better, not really useful unless you get a lot of fog or heavy rain/snow.

[walky_talky20]

If you want to make the facelift button work, you have some work to do. That button is momentary so it requires a "smart" relay to do the magic. It is not a regular on/off switch, and this is what complicates things. You can either swipe a facelift fog lamp module (relay box) and re-wire as per my directions here:
http://www.audizine.com/forum/showth...=1#post4997574

Or use an aftermarket "latching" aka "flip flop" relay, to do the job. I had a discussion about a device that would do that somewhere here on AZ. I'll have to find it and add it to that other thread.

[legbuh]

Yes, I saw your thread, Walky_talky20, and that's why I thought I'd take a look since the console upgrade was done. I expected to find the facelift fog lamp module in there.

But nope... it wasn't. So I'm wondering how did he wire it to turn the fogs on with the headlights, and also turn the little indicator light on when the fogs were on? I didn't see any of the pre-facelift connectors in there either. So I'm lost as to what's done... and how it's done... :)

I don't mind doing a little work to get the fogs to work with the button, but I need to know where I'm starting from to know what I need to get to that point.. :)

[sweets4style]

If you need the relay or wiring snippet PM me as I have it available and a few spares.

[Poopie]

Correct me if Im wrong, but didn't someone post that could swap button faces and use the prefacelift button mechanism with the facelift front part?

[legbuh]

If you need the relay or wiring snippet PM me as I have it available and a few spares.

I'm not sure what I need at this point... That's the problem. The wiring could be behind the dash, or it could simply be up by the headlights. I did see a relay up there. So I don't even know if there are the stock wires going to the fogs. :)

[legbuh]

Correct me if Im wrong, but didn't someone post that could swap button faces and use the prefacelift button mechanism with the facelift front part?

Not sure.. I've looked through everything I could find and didn't see that.

[walky_talky20]

Yeah. I don't think that's possible. The switches are quite different sizes and such.

legbuh: I think the fogs are just hard wired to the low beam circuit. Nothing special. He probably just installed a jumper in place of the fog lamp relay. From your description of the button wiring, it sounds like the factory fog switch connector was cut off and the low-beam wire from the harness (the power wire) was merely tied into the new switch's light.

[legbuh]

Yep, I know there's a jumper in place of the relay... I thought he said that was just so you could have the fogs on with the brights.

Well shoot... I was really hoping all I needed was the facelift relay module but if he also cut off the old connector, that may make things a little more tricky. Maybe it is, I need to just find time to unwrap the wiring to see what's going on there. :)

[walky_talky20]

The job of the fog lamp relay is to close (turn on the fogs) only when:

A: low beam headlamps are on
B: high beam headlamps are off

Only when both are TRUE will the fog lamp relay close. So it's main job in life is the "high beam cancel" feature. When jumpering past this relay, there are 2 options.

Option A: You can jumper FOG SWITCH > FOGS. This would be appropriate with a fully stock car to merely delete the "high beam cancel" feature, allowing fogs with Low beam or High beam (but still not "independent").

Option B: You can jumper LOW BEAM > FOGS. This would be appropriate if you had [savagely] ripped out the factory fog switch and replaced it with a useless (on it's own) momentary switch from a newer car. In this method, the fog lamps would be always on with low beams and high beams. Because the old switch is gone, you have no choice in the matter. In this case, removing the jumper and replacing the fog lamp relay would leave the fogs completely inoperable until the factory fog switch was reinstalled as well.

It is entirely possible that something else was done. I'll call this ->

Option C: A jumper is installed at the fog lamp relay location that goes FOG SWITCH > FOGS. The fog lamp switch is then [savagely] ripped out of the dash and it's connector cut. The IN/OUT wires of the switch's harness are twisted together (will act as if button is always ON) and a 3rd wire is twisted in with them: the wire for the green light on the new (useless) facelift switch. In this setup, should the jumper be replaced by the factory relay, the effect will be the restoration of the "high-beam-cancel" function. Fogs will remain on (whether you like it or not) with low beams on.

I'm willing to bet you have something pretty close to Option C going on up-in-there. To make this work properly with the facelift switch you will need to incorporate either the OEM fog control module from a facelift car, or something like this:
http://www.mcmelectronics.com/produc...LAID=220323765

That is a "flip flop relay". It takes a momentary input (a la facelift fog switch) and switches an output on and off repeatedly each time it sees a pulse from the switch. The output would be 12V+ and would be used to drive a relay that powers the fogs. This system would give fully independent operation (if desired). The only requirement being that the key is on and the fog lamp switch has been pressed. It is important to note that (just like the OEM fog module), the fogs will always "forget" their on state. So if you leave the fogs on last night and shut the car off like that. The next morning you will have to again summon them via the switch.

The cutting off of the old fog switch connector (however savagely) is not a big deal at all. You've got nothing, literally nothing, that will plug into that connector anyway. So you'd just be hacking it off yourself, perhaps less savagely though.

[legbuh]

Ok, thanks, Walky.. makes more sense now. I'm sure once I get the tape off the wires coming from the new switch things will make more sense, but your descriptions certainly do help!

Even though the old harness has been cut, the wires should still be there and available to work with along with the facelift relay module.

Now, the only question would be, if I follow the diagram on the facelift DIY for foglight wiring, would I want to replace the jumper with the relay? My main concern would be leaving the jumper in, doing all the new wiring, and the jumper causing problems (like a short or something).

[walky_talky20]

No. Nothing to worry about.

The jumper is merely a temporary part of the circuit, and we will change it if we need to. If I have time tonight I'll try and draw up a diagram for what needs to happen.

[legbuh]

Would a latching relay work? http://en.wikipedia.org/wiki/Relay#Latching_relay

I know you called it a flip flop relay.. just doing some reading. :)

[walky_talky20]

No a latching relay won't really work (by itself). That type of relay would require 2 switches: on and off. You could certainly make that happen by using both the front and rear fog switches to just control the front fogs. One for ON, the other for OFF. If you want it to work with just one switch (on/off switch), then you must use some electronics (ie: the flip flop module I linked, the OEM fog module, etc). Another option would be one step above a "latching" relay: called an "impulse" or "sequencing" relay. That is a relay that latches yet only has 1 input. Each momentary input pulse will toggle it back and forth from ON to OFF and it only uses electricity during the switchover because it latches in each position. Additionally, by design it would always "remember" the last position. In fact, that sounds like a really good solution. This guy here:

http://www.zorotools.com/g/00062829/k-G2972286
More info:
http://magnecraft.thomasnet.com/item...1001|1019|1105

[legbuh]

Well, I couldn't resist and had to see how these were wired.. here's a snapshot:



If we look at the wires from this pic:



We see all the wires are there. It looks like the grey/green and white/yellow are tied together like walky guessed and it's also tied into the white/red to the new facelift switch (there is a short brown/blue wire there, but that looks like just a splice wire).

grey/blue goes to grey/blue and brown goes to brown (as it should).

White/yellow and grey/green from the new switch not hooked to anything.

My question is, why are there two thicker white/yellow and grey/green wires (the ones that would have originally connected to the pre-facelift switch)? I would have expected just one of each coming out of the stock wiring.. And all 4 are joined together (which as walky said, tells the system that the lights are "on" all the time). But why 2 of each wire?

[legbuh]

I was reading another foglight mod and it said that the original switch for the front fogs will have 2 sets of each of the bigger wires going to it... this is because when the rears get turned on the fronts will automatically get turned on too. Makes sense.

I will just treat them as "1 wire" each. :) I wonder if my rear fogs will even work when this is done... the PO didn't seem to care about them not working so much.

[walky_talky20]

Yes, you are correct. The second wire of each color goes to the rear fog switch connector. The gray/green ones are the power supply. Low beam power comes in on that wire, and the second green wire is just simply stealing power for the rear fog switch. The yellow wire is output to the fog relay (and eventually to the fog lights). The second yellow wire is coming back from the rear fog switch. The rear fog switch has 2 outputs. 1 output powers up the rear fog lamp. The second output is that yellow wire, which sends power back up stream to the fog relay (and eventually to the fog lights). This is how the rear fog switch powers up both front and rear, and the front only powers up the front.

There will be no problems making everything work on your car.

[jacobaudi]

ok by using the flip flop relay is it possible when putting on the fog light with one touch, would the indicator light on the switch illumine

[walky_talky20]

You simply connect the indicator on the fog light switch to the output of the flip-flop. When fogs are on, the light is on. If you decide to leave the factory fog lamp relay in place for high-beam cancel, that is downstream, so the indicator would remain on even when the fogs are cancelled by high beams. This is the factory behavior.

[jacobaudi]

You simply connect the indicator on the fog light switch to the output of the flip-flop. When fogs are on, the light is on. If you decide to leave the factory fog lamp relay in place for high-beam cancel, that is downstream, so the indicator would remain on even when the fogs are cancelled by high beams. This is the factory behavior.

Thank you so much