We have a module on our Jeep to tow our pop-up. It was installed with the Draw-tite hitch by the Jeep Dealership. Worked fine until last fall when we were to go to Va Beach. Hooked the pop-up like always but my lights were screwy (some worked, some didn't, all were really dim and I only had turn signals on one side). I chased down all the grounds, checked all light bulbs and connections and ended up towing the pop-up over to NC (200 miles, part of it down I-75) with no lights hooked up. Got it over to NC and David did all the same stuff I did at home before finally listening to me (told him I did all that same stuff). Our module was bad. Seems the ground was broken inside the module and another wire had broken off the connection. Somehow water had gotten inside the module. With a new module all the lights worked great and were real bright. So it's not always the ground. Also you may need the boost of power the modules provide (module has a hot line to the battery so it is a powered booster).