When it is dim as you described, you have a weak connection. Most commonly, it is a bad ground. Reconfirm that the ground is good by checking continuity. If there is no resistance and it shows good, check the power supply and make sure there is 12v to the socket. When probing the socket, make sure the wiring in it is in good condition and not moving because the socket itself could be bad.
Do this and let me know what you find. It has to be one or the other. My money is on either a bad socket or a poor ground.
Thursday, July 3rd, 2014 AT 8:08 PM