Re: Lights
Step #1: Make sure the connector on the truck is providing the proper signals. Use a test light or meter, or one the LED test plugs. Many people chase their tails for days trying to find a trailer light issue when the tow vehicle plug is not right.
Step 2: Check the white wire connection to the trailer frame. Make sure it's not broken, and that the connection is clean and tight.
Step 3: Check the light housing mouting bolts. Those bolts provide the ground connection to the trailer frame.
Step 4: Obviously, check the bulbs and make darn sure they installed correctly. Dual filament bulbs can easily be installed 180 degrees wrong.
Step 5: You can use a battery charger during the diagnosis process. Clip the ground lead to the trailer frame and touch each pin the plug (except the white one) to power each light circuit.
