I have a trailer and I am pretty bad when it comes to doing electronic things. My drivers side tail light on the trailer will illuminate with the lights on but it does not blink brightly when the signal is on. It also will not get bright when the brake lights are on. My other tail light (on the trailer) works perfectly. This is a simple tail light kit that you would get from Harbor freight or Walmart, nothing special. I have uploaded the picture of my multi meter but I am not sure how to use it to see if I have a good ground. I have heard that the ground might be the problem but I just don't know how to check it. Can someone give me a little tutorial on how to go about getting this fixed? Thanks!