paddlenbike
12-16-2007, 04:44 PM
The factory diff lock switch has an internal bulb and two electrical contacts for nighttime illumination. For whatever reason, Toyota did not utilize these pins, leaving the switch hidden at night. Here's how to get yours to illuminate with the instrument lights.
Remove the plastic trim cover under steering column by removing four bolts, two screws for the fuel filler door release and two screws for the hood latch. Remove the diff lock switch from the dash. From top to bottom, pins 2 and 5 engage the rear locker, pins 3 and 4 illuminate the switch. Pin 1 goes unused.
To do this neatly, you'll need to either buy some small electrical contacts, (see photo below) or remove two of them from a wiring harness on your truck that is not being used. No matter what your truck has for options, there will be an unused harness somewhere. (My truck had at least two unused harnesses.) In my case, I had some random wiring parts in my garage that used the same harness pins, so I salvaged those. Using a push-pin, push the contact out of the unused harness from the inside.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock1.JPG
Now you need to locate a power source that is only hot when the vehicle lights are on. Using a test light, hook one end to ground and turn on the parking lights and probe until the test light illuminates. I found power and ground in one of those unused harnesses I mentioned above. When you find one, turn off the parking lights to verify that the test light also turns off. Solder your wire to it and push the electrical contact into the diff lock harness using pin 3.
In the photo below, the black switch in the foreground is the diff lock switch. The switch is upside down in this pic, the green wire in pin 2 and the black-yellow wire in pin 5 are the factory diff lock engagement wires. The red-black wire in pin 3 is soldered to a source that is hot only when the lights are on. The black-white wire in pin 4 is wired to ground, which I located in the same harness that I found the switched power.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock3.jpg
After soldering and taping/shrink wrapping your connections, snap the switch into the dash and reassemble the interior. Now you can enjoy your newly illuminated diff lock switch.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock8.jpg
Ken
Remove the plastic trim cover under steering column by removing four bolts, two screws for the fuel filler door release and two screws for the hood latch. Remove the diff lock switch from the dash. From top to bottom, pins 2 and 5 engage the rear locker, pins 3 and 4 illuminate the switch. Pin 1 goes unused.
To do this neatly, you'll need to either buy some small electrical contacts, (see photo below) or remove two of them from a wiring harness on your truck that is not being used. No matter what your truck has for options, there will be an unused harness somewhere. (My truck had at least two unused harnesses.) In my case, I had some random wiring parts in my garage that used the same harness pins, so I salvaged those. Using a push-pin, push the contact out of the unused harness from the inside.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock1.JPG
Now you need to locate a power source that is only hot when the vehicle lights are on. Using a test light, hook one end to ground and turn on the parking lights and probe until the test light illuminates. I found power and ground in one of those unused harnesses I mentioned above. When you find one, turn off the parking lights to verify that the test light also turns off. Solder your wire to it and push the electrical contact into the diff lock harness using pin 3.
In the photo below, the black switch in the foreground is the diff lock switch. The switch is upside down in this pic, the green wire in pin 2 and the black-yellow wire in pin 5 are the factory diff lock engagement wires. The red-black wire in pin 3 is soldered to a source that is hot only when the lights are on. The black-white wire in pin 4 is wired to ground, which I located in the same harness that I found the switched power.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock3.jpg
After soldering and taping/shrink wrapping your connections, snap the switch into the dash and reassemble the interior. Now you can enjoy your newly illuminated diff lock switch.
http://home.off-road.com/~kemanuel/4Runner/mods/difflock8.jpg
Ken