Here is an alternate way to install the fog lights... It looks pretty straight forward. It does require purchasing a few other items but it looks like a very clean install. This is post #225 from http://townhall-talk.edmunds.com/direct/view/.ef0a0ee/217.
1) Push out the UGLY black fog lamp covers and discard.
(Sell these things on ebay.)
2) Install the really great looking Fog Lamps that Toyota won't sell as an option. Remove the Phillips screw from the back of the new lamps, press the white plastic retainer into the small slot from behind. (Two small clips hold it in place.) Hook the gray plastic tab on the Lamp into the outboard slot and swing the Lamp assembly into position, Move the retainer as needed until the screw will mate and hold the Lamp. (Use a stubby screwdriver 'cause you don't have much room.)
3) Connect the Lamps to the existing wiring harness. Look for an oval shaped black connector taped up against the inside wall.
4) Repeat for the other side.
5) Install the Fog Lamp Relay, (Part Number 90080-87026.) in the under hood fuse box. (Lower right side of the panel.)
6) Replace the turn signal switch with the Fog Lamp/Turn Signal Switch, (Part Number 84140-02200.) Tilt the steering wheel down, remove three Phillips screws from the plastic steering wheel cover. (One brass screw is just to the right of the steering wheel tilt adjust lever, the other two are black and may be hidden by the steering wheel, swing it from side to side while looking at the cover thru the steering wheel, you'll find them.) Pull down on the plastic cover to separate and remove the lower half and push up and to the right to remove the upper half. Use the tip of a screwdriver blade to depress the black plastic retaining tab on the turn signal switch, remove switch and disconnect the white wiring harness. Install the new Fog Lamp switch, (Just line up the tabs with the metal bracket and push till it seats.) reconnect the wiring harness. Test you work. Replace the steering wheel covers, top first, This is the only part that is not a lot of fun, but it will snap back into place. Replace the steering column cover screws,
that's it. The Lamps will work every time and look like a factory option.