Haroon: I seem to recall from prvious knowledgeable posts that the main connection for ALL rear lights is at the left (=driver's) side rear light, speciiifically the ground wire, secondarily other connectors. Try cleaning the ground wire there, then the other connectors. If you have a circuit board, it may be worthwhile to remove the entire light fixture, looking for corrosion, leaks, bad gasket (which leads to water infiltration , which leads to corrosion). Also, many posts recommend changing light bulbs in pairs, and of the proper part number (=OEM), and checking all of the bulb sockets for corrosion, loose connections, etc. Hey, this might cost you nothing but T-I-M-E, and/or a few light bulbs. Good Luck, amigo.--PD.