Explain proper operation of vehicle systems to customers. Locate and repair frayed wiring, broken connections, or incorrect wiring, using ohmmeters, soldering irons, tape, or hand tools. Repair plumbing or propane gas lines, using caulking compounds and plastic or copper pipe. Confer with customers, read work orders, or examine vehicles needing repair to determine the nature and extent of damage. Examine or test operation of parts or systems to ensure completeness of repairs. Connect electrical systems to outside power sources and activate switches to test the operation of appliances or light fixtures. Connect water hoses to inlet pipes of plumbing systems and test operation of toilets or sinks. Inspect recreational vehicles to diagnose problems and perform necessary adjustment, repair, or overhaul. Inspect, repair, or replace brake systems. Diagnose and repair furnace or air conditioning systems. Repair leaks with caulking compound or replace pipes, using pipe wrenches. List parts needed, estimate costs, and plan work procedures, using parts lists, technical manuals, or diagrams. Remove damaged exterior panels and repair and replace structural frame members. Open and close doors, windows, or drawers to test their operation, trimming edges to fit, as necessary. Reset hardware, using chisels, mallets, and screwdrivers. Refinish wood surfaces on cabinets, doors, moldings, or floors, using power sanders, putty, spray equipment, brushes, paints, or varnishes.