markcz

The instructions I'm giving are written to have the fog lights come on with the high beams. All wiring is done inside the car under the dash, and there is a hidden switch that will allow you to easily return the light functionality to stock. If you want to have your low beams come on with the high beams, check out this thread. http://forums.corvetteforum.com/zerothread?id=666975 The instructions are a dozen or so posts down on the first page, and all of the wiring is done under the hood.

This is what you're doing: Fog/High Beam Schematic Drawing

The theory:

The +12V that powers the high beams (Light Green wire) pulls in the relay. If the toggle switch is off then nothing happens. When the relay is pulled in then the +12V from the Aux Power wire is connected to the fog lights (Purple wire) and the fogs are lit at the same time as the high beams.

Here are the stock schematics:

Hi Beam Schematics
Fog Light Schematics
Aux Wires Schematics

Some pics from along the way:
Fog Lights stock switch connector
The wires you'll be using
The installed toggle switch

Here are the parts you'll need Note: there are two relays in the picture, you'll only need one.

I used a 30A automotive relay from Radio Shack, part #275-226 for $5.99

The switch is part #275-648 for $2.99, but it requires soldering the wires on to it. You can get a different switch that has 1/4" spade plugs and it will work just fine if you can't solder.

The wire is 18 gauge, and the other pieces are butt splices, crimp-on 1/4" female spade terminals, and in-line quick connects.

The procedure:

Disconnect your battery (-) terminal. If you don't you will probably blow a fuse or shock yourself.

Under the passenger side footwell, at the top left corner there is a plug with three wires taped together. This is the Aux Power connection point, and the wires are Yellow, Orange, and Black. Run two strands of wire from the passenger footwell to the drivers side under the steering wheel. Connect one of those wires to the Black aux power connection. The other wire can be connected to either the Orange OR Yellow wire, if you use the Orange wire the fogs will come on if you pull on the 'flash to pass' lever even if the car isn't running. If you use the Yellow wire the fogs will only come on with the brights when the car is running. Make sure to remember which wire is which on the drivers side of the car.

Pry out the fog light on/off switch and disconnect the wires. See pic. The wire that you are interested in is the Purple one. You can do this mod without removing the bottom half of the dash cover, but it would be easier if you just remove it. See the instructions on how to install a Column Lock Bypass kit in the Tech Tips section for details on the dash removal.

You will need to remove the plastic cover that's above your feet when you're driving. The front has two 'push in' plastic retainers that just pull out, and the back has a metal washer that grabs onto a metal post. The metal washer will come off if you pull hard enough and twist it. The recessed part of that plastic piece is where I mounted the toggle switch. See pic.

I pulled the fog light switch wires out through the bottom of the dash board to make it easier to work on them. You should be able to push back the electrical tape wrapped around the wires to get at the Purple wire at the base of the dash, instead of next to the connector at the switch.

Under the steering column, at the base of the dash, you'll need to locate the largest connector under there and unplug it. It has two rows of about 12 wires each. On one end there's a White wire on top of an Orange wire, and on the other end there's a Light Green wire on top of a Tan wire. The connector comes loose by pushing down on the center catch and pulling it out. See pic.

Use the schematic drawing to be sure to connect everything properly. Make sure to mount the toggle switch before permanently attaching any wires.

Tap in to the Light Green wire on the corner of the large connector using a quick connect and run that wire to the toggle switch. The other wire from the toggle switch gets connected to pin 86 on the relay.

Connect the wire coming from the passenger side that is attached to the Black aux power wire to pin 85 on the relay.

Connect the wire coming from the passenger side that is attached to the Yellow or Orange aux power wire to pin 87 on the relay.

Tap in to the Purple wire on the stock fog light switch wires using a quick connect and attach the other end of that wire to pin 30 on the relay.

Plug the large harness back in under the steering column, then reconnect your battery and try it out. The fog lights should come on whenever the brights are lit. Note: if you used the Yellow wire on the aux power connector then it will only work if you turn the ignition key to ACC or ON. The toggle switch must be on for it to work, and when it's off the lights will function just like they did before the mod was installed.

If it works then put your dash back together and go for a drive on a poorly lit road as soon as the sun goes down. If it doesn't work then check fuse 7 or 11 in the passenger footwell fuse box. If the fuses are good check to be sure that the quick connect taps are squeezed together completely. A voltmeter or test light will work great to help see where the problem is.

Happy modding! :cheers:

Wah

Good tips. Now if just there is instructions on how to make headlights doors to raise when flashing high beams (with light switches turned off) ;)

catfish

I was wondering if you may be able to help figure out the wiring for the brake/turn signal tail light. I wish to break the two circuits apart so I can use a separate wire/lamp for the turn signal and a separate wire for the brake/lamp. Perhaps you may have a wiring diagram that shows where the connection of the two circuits is. At that joint I could then separate them...

FO SHIZZLE

:cool: :cool: :cool:
any way to have the highs and lows on at the same time ?

HP_Addict

Great idea, thanks for the write up. Can you notice a difference with the fogs & high beams both on?
Chris

silverz06vette

Thanks for doing this!!!

msuc5vette

On my car you can't even tell the difference between parking lights and parking lights with fog lights :rofl:

This was on my list of things to do, but if you want to have the highs, lows, and fogs on when the high beams are on, and don't care about having a switch to disable this feature it would be much easier to just wire the relay directly to the high beam as the source, and back to each light you want on all from the front of the car.

markcz

http://forums.corvetteforum.com/zero...795#1545407795

:cheers:

markcz

You need to cut the WHITE wire coming off of the switch on top of the brake pedal. Find some online instructions for installation of the Euro brake lights for the details.

:cheers:

markcz

It is definitely an improvement. Before the mod, I rarely even needed to put on my brights since the 1100x fogs work so well, but when I did it seemed like the amount of light was less with just the brights on compared to the lows with the fogs. The brights did project the beam farther down the road, like they're supposed to, but it just wasn't as effective as the lows/fogs. Now everything is very well lit both near and far. :thumbs:

markcz

I agree 100%, but the switch to disable the mod on the inside of the car was one of my personal 'requirements', so that's how I did it. As I posted here: http://forums.corvetteforum.com/zero...795#1545407795 it would definitely be easier to do it under the hood, just run the output of the relay to the fog light supply wires (the Purple ones) instead of the low beams. You could even easily wire it up so all 6 lights came on together, but make sure you don't put too much current through any one wire or relay. I'd suggest no more that one SET of lights per relay, and I wouldn't just increase the size of the in-line supply fuse either (larger fuses have a tendancy to NOT blow when shorts pop up).
:cheers:

gmblack3

When I still had the stock headlights the PIAA 1100s made a big difference. Now that I have the T-84s with the PIAA H4 15260 (I think) bulbs, my high beams are usable and will outshine the PIAAs. I just want that area right in front of the car light up as well w/ the high beams on.