Trailer wiring issues. Need help
 

Hey guys I am new owner of a 05 silverado 2500 hd. 6.0 vortec. I tow a cargo trailer which I use for work. I plugged it into a 7 way adaptor ( Hopkins). Because the trailer is wired with a 4 prong.And the side marker lights ( running ) lights do not come on. I did not have any issues with my old truck. Dodge ram 1500. I heard rumors of some wiring issues in the tow package. Any advice? I also put a prodigy brake controller on it. Haven't tried to tow with trailer brakes yet. Confused????

lights
 

i guess all the functions worked on the old truck ? i have not been a beliver in the hopkin's brand wiring ,ground problem's ect .take a test light and check to see if each function works in the factory plug in the correct location .there is usually a picture legend on the plug cover ,if it works on each function then with the adaptor pluged in see if you are getting th3 signal through itin the correct location of the four wire plug .if not the adaptor is junk .