On most Toyota trucks the turn signal and parking light are separate lights with separate lenses.  One bulb drives the turn signal and another bulb handles the parking light.

With some custom and aftermarket bumpers on Toyota trucks it would be nice to not have to mount the extra set of lights for turn signals. Some after market bumpers don't provide a good turn signal solution. My TJM front bumper has front turn signal lights built in, but the lenses are designed for use in Australia and are not DOT approved for use in the United States. After having a traffic cop point  out the missing approval I decided it was time to modify my existing parking lights into a combination parking light and turn signal.

After considering several options I decided to use a standard 1157 light bulb. This is the same bulb found in the rear of most cars and trucks for the last 40 years so it's a common one. A local Carquest auto parts store had a number of different 1157 light sockets on the shelf to choose from. I picked a set of sockets that had sevral spring prongs around the outside. 

nbsp;  I removed my stock parking lights and cut off the light sockets, leaving just a bare pair of wires going to each light. Using a voltmeter I found the white wires were ground and the green wires were power for the parking lights. I also cut off the wires going to the turn signals. Again there were two wires one white and one green. 

Next I used a drill to open up the hole the parking light fits into. I also used a  knife to make the opening an oval shape. The oval shape allows the new socket to fit all the way in and snap into position. The little prongs of the socket keep it from falling out.

The 1157 bulb has two filaments inside, a small one and a larger one. The small 7 watt filament is for the parking light and is dimmer then the larger 25 watt turn signal filament. The bulb uses a common ground for both filaments. The bulb sockets I purchased have a spade connector for use as a ground. This is very helpful in this application because the Toyota light housing is all plastic and does not provide the necessary ground.

I connected the parking light green wire to the small filament and the green wire from the turn signal up to the large filament. I then connected the parking white wire to the spade connector on the light housing for a ground.  Now my parking lights serve double duty as both parking and turn signal lights.

See ya on the trails!