no trailer breaks

[mattdoxa]

my 06 6.0 doesnt have trailer breaks when the trailer is plugged in and i hit the built in break controler it says trailer disconnected. my dad has the same plug on his 01 and 07 with the same trailer the breaks work.. i hooked a test light up to the prong in the plug on the truck and it lights up but still no breaks.. any suggestions?

[JSchuricht]

What plug are you using, 7 pin flat/round, 6 pin, 4 pin? You need to verify the ground is good from the truck to the trailer and that the brake power wire is supplying ~12v.