Right side rear tail light does not light for turn, braking, or running. Both bulbs visually look fine. I was told it could be a grounding problem, and to check for a loose ground. Can anyone confirm whether or not that sounds like the problem...or to look for something else? There are three thin wires ( black, brown,green) that go into the plug for each bulb. Everything looks fine, but I don't really know how to proceed. should I pull the plugs apart before I rule out that being the problem? I'm far from being a mechanic, and my skills are very limited. So any guidance would be appreciated. I don't want to call a shop if I don't have to. Thanx

 

The black wire should be the ground. Check it with an ohm meter to see if it is actually grounded. Then turn on the lights and use a volt meter, you should get 12 volts between the black and brown wires.

 

Also check the fuse if you aren't getting 12 V.