My driver's side front running light comes on but just "glows" really dull. Must be a ground??? Can/t find one. Just 2 wires, one for turn signal, one for running lights. Turn signal works fine.

Its is a ground..good guess, by now the elements have tried to galvonically alter the archetecture of your lighting component electrical fastening~...in other words wirebrush all connections to the lighting unit, assure the bulb is making full electrical contact, break out a stainless steel scrubbing pad from the kitchen sink, assure electrical connection to the lighting fixtures----and take the end of the black battery cable that attaches to the frame/chassis and clean them both with a wirebrush, and the bolt too, the connection to the engine block and the battery terminals (run a hose to hose it off rather than making any of these nasty things airborne) The red cable, the little lolipop return on the red side and the other end what connects to the starter solenoid....undo that bolt partially enough to get a "brass toothbrush" in between there and clean out any corrosion of spiderwebs~.....in review clean that honkin' black cable's end and the connection to the engine block....clean the battery terminals (with a hose please) and the Positive with the little lolli (return from the alternator) to assure it's all good~

batteries will refuse to accept a charge 10% per year...so in ten years the battery will no longer be accepting a charge...get a new battery, that way you won't cook your alternator tryin' to hold up the show...with little or no help from the battery~

it could be corrozion on the contacts on the plug side and lime away in warm water can take that off the plug.