Fog Light Modification
NOTE:This is for a Pathfinder / QX4, but MAY be adaptable to other Nissan models as well.
The fog lamp relay is powered through the headlamp relay, so your headlights would need to be on to power the fog lamp relay. The ground side of the relay goes through the foglamp switch then up through the headlight switch which must be switched to low beam position to supply the ground to the circuit. The fog lamps are powered directly through the fog lamp relay.
You’ll need to circumvent the control circuit of the relay which has both control of power side and ground side of the fog lamp relay. You will need to cut 2 wires and add your own wires to make the circuit work.
The fog lamps will stay illuminated as long as the fog lamp switch is turned on.Meaning, even when the high beams are on the fog lamps will still be illuminated.Also, there is no battery saver function control of the fog lamps(they will not be shut off if accidentally left on by the smart entrance control unit. like they are normally).
Your VIN number will play a part in this bypass as the power supply wire from the headlamp relay to the fog lamp relay is different colors.
If the last 6 digits of your VIN are lower then 500000 then the wire is R/B (red with black stripe).If your VIN is higher than 500000 then the color is R/L (red with blue stripe).
At the fog lamp relay, remove the relay and look inside the terminal area of the relay.You will see numbers if you look very carefully.At terminal #2 you should see the power wire mentioned above.Remember you are looking at the relay upside down so be sure you match up the right terminal as the other side is the same color wire.Cut that wire about an inch from the relay connector, R/B or R/L wire.To verify you have the right wire before cutting use a voltmeter to test for power with the headlights on in that terminal. With the relay out, the other wire wont have power.
Now go to your fog lamp switch and find the Y/B (yellow with black stripe) wire and cut it about an inch from the switch.
It is strongly recommended you use a soldering iron to properly connect these wires and use either heat shrink or self adhering electrical wrap, not black electrical tape.The electrical wrap is as good as heat shrink as it completely seals the conection from moisture.
On the fog lamp Y/B wire you will be running a wire from the wire coming off the switch to a good ground under your dash. Do this by “tinning” both the wire you are adding and the Y/B wire coming off the switch. Slide your heatshrink tube onto the wire your adding and away from the heat of your iron.Solder the 2 wires together.Allow to cool slightly.Slide your heat shrink tube over the connection and shrink it.Attach the other end of the wire to a ground point under the dash, such as a body nut or bolt on either the metal behind the kick panel or the cowl near the steering column mount.
On the power wire at the relay (see color description above) prepare the joint the same you did with the ground.However this wire will be jointed into the R/Y wire at the RH headlamp relay(there are 2, either is fine as they come from the same fuse source).You will be using another piece of wire to jump the 2 wires.No need to cut the R/Y wire, just cut away about a half inch of the insulation about an inch or so from the relay.”Tin” the wire quickly as to much heat will start melting the insulation, then joint it together as you did above with the other end of this wire.Using this method you wont be able to use the heat shrink tubing.Alternatively you can cut the R/Y wire and joint it like the others to use heat shrink tubing.
The other way to do this would be to just use end connectors and a scotch lock at the head lamp relay (no soldering), but using this method puts you at risk of moisture collection on the joints ultimately causing corrosion increasing current draw on the circuit and possible complete circuit failure over time.
Good luck, and have fun!