ULTRA-BLUE-SEAL® Wire Harness System - Grote Industries Grote Industries is a leading worldwide manufacturer and supplier of LED Lights & lighting products for heavy duty trucks, trailers, vocational and passenger vehicles. Trailer Wiring and Communications Systems – Lamp Jumper Harnesses (boat trailer harness)* Brown – Tail and license lamp, and clearance lamps; Wiring & Communication Product Category - Grote Industries Corrosion is not an option for Grote Wiring products. Ensure a perfect connection for your entire trailer with Grote Wiring and Communication systems. Cut-To-Fit® Wire Harness Systems. Slim-Line Under Light Females (Cut-To-Fit®) Standard Male to Slim-Line Under Light Female.