Hook up 1st gen foglights to be turned on or off from factory switch on dash regardless of any other lighting systems being on or off.  No confirmation yet if this works on 2nd gen cars.

Last updated 07/18/98 - RandyNet - randynet2@earthlink.net

Description.  This will describe how to hook up your 1st gen DSM foglights so they can be turned on or off from the factory switch on dash regardless of any other lighting systems being on or off.   The way this mod is arranged, the lights will not work if the key is not turned on...ie, if you leave the switch on, they will automatically turn off when the key is turned off.  They will turn back on when the key is returned to the on position.   This mod will power the lights with the factory wires and relay systems.  You will not be cutting any wires under the hood.  You will have to cut two wires on your instrument panel.

    Find and identify the relays.  Reference the below diagram "1st gen relay diagram".  Under your hood on the passenger side is a relay box.  The box cover will include a diagram and labels of the relays in that relay box.  We will be interested in two of the relays in this box.  There is a row of three relays closest to the passenger compartment.  They are called "FOG","RAD","ALT".   We will be interested in the FOGlight relay and the ALTernator relay.  The RADiator relay runs the radiator fans.  Grab the FOG and ALT relays and pull them out.  They will be snug, but should pull out just like a fuse.  Once they are out, you will see the exposed contact points as described in the below figure.
 

    Contact point description.

    1) Fog Connector # 1
    2) Fog Connector # 2
    3) Fog Connector # 3
    4) Fog Connector # 4

    5) Alt Connector # 5
    6) Alt Connector # 6
    7) Alt Connector # 7
    8) Empty

    Jump the relays.  We are going to run a jumper wire across points 4 and 7.  The way I accomplished this was to strip the ends of the jumper wire and slide it down into the exposed female contacts.  Once they are slid down in there, just plug in the relays and it will hold them tight.  CAUTION:  Don't strip your wire back too far, and take note of how far you are sticking the wire down into the female contact.   It is open at the bottom, and if your exposed wire is long enough, it could ground out or short out to something below the relay.  If you feel more comfortable jumping the relay by some other method, please do the way that feels safe to you.

    Make a choice.  As you look at the relays, you will notice that a simple 3" jumper wire will be able to cross these two points.  If you use a short wire, everytime you turn the key on the fogs will come one.  When you turn the key off, they will go off.   The switch on your dash is bypassed and does nothing.  You effectively have daytime running lamps.  -or-  You can make that jumper wire about 12 feet long and run it from the 1st relay into the car to the foglight switch and then back to the 2nd relay.  If you do this, your factory on dash switch will turn the fogs on and off, and the circuit will only complete if the key is on.  The benefit of this is that you cannot leave the fogs on when you leave your car.  I just leave my switch on all the time which basically gives me daytime running lamps.  If I need to hide out and turn them off while driving or idleing, I can.  NOTE, If you are going to run your fog lights, make sure you take a minute to aim them properly. Pull your car up to a flat wall at night and adjust the aim of your lights ... and aim them downward towards the ground.  Other drivers will appreciate it.

 

    Ok, here is how to connect the jumper to the switch inside the car.  Here is a diagram of what my fog light switch looks like on my 1990 Talon.  You will need to cut wires 1 and 2 completely in two.  Tape off the ends that go to the wire harness, we will not be using those.  We will be using the peices of wire that come out of the switch.  Referencing the relay diagram above, we are going to be running a jumper wire from terminal 4 to terminal 7.  I'd recommend hooking up a short jumper wire under the hood (as described above) first just to make sure it is going to work before you go to all the trouble to run the wiring into the car.  Here's how to hook up the wire from the relays into the car and back out again.  The power flows out of relay terminal 7 to switch terminal 2.   The switch controls on/off.  If on, switch terminal 1 returns power to relay terminal 4.

    Does that make any sense?  You basically connect relay 7 to switch 2 and relay 4 to switch 1.
 

 

Remember, this numbering scheme means nothing outside of this page.  I numbered these wires just for explanation purposes.  If there are any questions, let me know!   randynet2@earthlink.net

Update.  I have heard a few issues of this mod causing some weird problems. Problems like the lights staying on regardless of switch position, or ignition key position. There have been some reports of other obscure problems too. In every case of a problem, the car had an aftermarket alarm system that was connected into the lighting system to flash the cars external lights. Aftermarket alarm systems are typically hacked and cut into many of the wiring systems, and you end up with yet another circuit board trying to run the lights. There is no fix for this or explanation, there would be hundreds of differant fixes depending on your alarm system and how it was installed. Just be aware that if you have weird problems and an aftermarket alarm system, you are on your own! I did this mod on my 91 Talon, and my 90 Talon (which had the factory alarm on it) with no problems.