I have aa 03 safari only 3rd brake light working please help. Thanks.

Hello, First thing, pull the bulbs. These go bad at the same times more than you'd think. The bulb part number is printed on the metal part at the bottom. With the safari, the 3rd brake light is wired separately from every other exterior light on the vehicle. It gets power from the brake light switch, but shortly after it takes another path to the rear of the van. The tail lamps, rear turn/hazard signals, reverse lamps, parking lamps, license plate, brake lamps and marker lights all run through one connector. You can test for power at the socket for the brake lamp, and you should have power only when the brakes are pressed. If no power there, follow the wire harness until you find the connector for all of the rear lights. Check for power/corrosion. Brake lights are the white wire.