I recently purchased a 94 Sundowner trailer and need some help with a brake problem. When the trailer is hooked up to my 2003 Ford F350 everything is working properly including the brake lights, however the brakes are not working. The problem is that when I apply the brakes I am only getting a dot showing up on my brake activator. If I use a 12v tester it lights up and the numerical reading shows up on the activator as if everything is working properly. I went through and made sure that both the male and female portions of the plug match. If anyone one has any ideas as what the problem might be it would be greatly appreciated.  

Thanks