I fought the bad contact issue myself on one of my front turn signal sockets. The contacts on that socket that holds the bulb can get co pressed over time and lose contact with the points inside the light that are to make contact when you twist it in place. I tried prying the contacts out a bit but that was too much to get it to turn into place so I pressed them back in a bit and that was too far to make contact. I ended up snipping the tips off a couple toothpicks and slid them under those contact points on the bulb plug. Twisted it into place and still working. A more permanent fix would be to put a glob of solder on them but have to be careful not to add too much or you won’t be able to turn the socket into place.