RV Clearance & Exterior Running Lights Maintenance

As you enjoy your Recreational Vehicle, the years and the miles start to show themselves in the outside lights. Running lights flicker, then fail completely; backup lights work sporadically; indicator and stop lights do not always give fair warning to other motorists.

Always Start by Checking the Bulbs

If a bulb is blown, it will never work. But if it works on and off, and the filament inside is sound, suspect bad connections.

No need to rush over to a repair shop to get the connections repaired. This is a job you can do yourself, even with no electrical knowledge. Repair shops like to make it look like a very tough job when, in fact, it is one of the simplest tasks.

WARNING: If the shop starts talking about re-wiring your lights, jump in the cab and drive away as fast as you can. Either they do not know what they are talking about and will damage your vehicle, or they have marked you for an expensive and unnecessary repair.

Why Re-Wiring Is Rarely Necessary:

1. Factory Wiring is Solid: The wiring of the outside lights is very solidly installed at the factory. The wires are stapled in place and will likely never need replacement. Almost all troubles with outboard RV lights are due to faulty ground connections, which are easy to remedy.
2. Single Power Wire: An outboard light has one wired connection carrying the +12 volt battery supply. (Two wires for combination brake-signal-backup bulbs.)
3. Chassis Ground System: The connection to the negative side of the battery (the ground return) is made through the vehicle chassis. The negative connection for an outside light is simply a sheet metal screw fastened through the grounded aluminum siding of the vehicle.
4. Check Other Lights: Are any of the other running and signal lights working? If so, the main fuses are likely fine.

Again, make sure the bulbs are still good and that the metal spring contacts are tight against the bulb contacts. Running lights have only one filament in the bulb, while signal-brake-backup bulbs have two, and therefore two wires and spring connections at the back of the socket.

The Usual Problem: The Grounding Screw

The ground return is made through a screw fastened to the thinnest part of the system—the aluminum exterior siding of the RV. Bumpy roads, rain, and dirt all help weaken these connections over time. As the vehicle ages, these screws work their way loose. Once the ground screw loosens even a little, current arcs, causing corrosion in the joints between the screw, bulb connector, and chassis.

The Fix: Step-by-Step Cleaning

1. Remove Plastic Lenses: The larger covers usually have small tabs on either side—push in the tab on one side and gently lift the cover off. Small running light covers can be pried off gently from behind any edge.
2. Inspect the Connection: Check the grounding screw and the metal tab underneath it. You will likely see corrosion, or find the screw loose.
3. Clean Corrosion: Remove the screw and polish up the connection using fine emery cloth (avoid coarse sandpaper) to get a clean, shiny metal surface for good conductivity. Clean the aluminum siding around the screw hole as well.
4. Replace the Screw: Install a new screw of the same size. If the hole in the siding has been enlarged through vibration or overtightening, use a screw one size larger in diameter to cut a clean, tight connection.
   NEVER use a longer screw, as you risk puncturing wiring or plumbing behind the aluminum skin!
5. Reseal Lens Covers: Clean away old brittle sealant or putty. Run a clean, thin bead of clear silicone caulking around the outer edge of the colored lens covers to keep water and road dirt out.
6. Clean the Lenses: Brush dirt out and wash colored lenses with mild dish soap to maximize visibility on the road.

About the Author

Wallace Mize is the owner of Mize RV Parts & Accessories. Mize RV is a family-owned and operated business providing affordable, name-brand RV parts and accessories.