Even though you may read 12-14V at the socket with no bulb present...
that doesn't mean everything is good. You may have a bad connection in
the power circuit when the load (bulb) is present and drawing current.
With the bulb operating... what voltage do read at the bulb? If you
still read 12-14V with the bulb operating... then you have a grounding
issue. If the voltage is way down with the bulb in... then you have a
bad connection in the power lead... and you should start investigating
connectors in that circuit. Hope that helps...

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