RV Troubleshooting Tools 3/8-inch drive ratchet set with sockets ½-inch drive socket set Butt connectors (for wire splices) Clean rags Common sizes of screwdrivers (Phillips and slot) Crescent wrench Electrical circuit checker Electrical tape Extra cotter pins Extra hoses Hammer Locking pliers Needle-nose and regular pliers OBD-II Diagnostic scan tool (optional) Spark-plug socket (check your engine’s size) Combination wrenches Duct tape Electrical test light or digital multimeter Extra fuses and light bulbs Flashlight Gloves Jumper Cables Extra motor oil and automatic transmission fluid Spare electrical wire in several gauge sizes Wire crimper Water WD-40 (or other multi-use spray-on lubricant) Windshield-washer fluid Wire splicers