Do you have a battery charger? If so, put the battery charger on it's lowest amperage setting (2 or 6 or 10 amps). Put a light bulb (1157) in the socket making sure the bulb's alignment marks are correct, and turn the bulb and lock (turn) it in place in the socket. One groove in the side of the socket is longer than the other so be sure the bulb is installed correctly. If the bulb doesn't want to turn take it out and try to install it the other way. Clip the black (negative) battery charger clip on the steel of the socket housing and touch the red lbattery charger clip to the red wire and then touch the red battery charger clip to the white wire. The brake light filament will be much brighter than the parking lights filament. Note the brighter one and connect it to the correct harness wire.