Boat trailer lights would have to be one of the most frustrating aspects of owning a boat. They are a constant hassle and require continual maintenance to keep you legal and safe on the roads. Having faulty trailer lights can cost you a hefty fine, not to mention the increased likelihood of another motorist running into the back of your boat if your brake or indicator lights fail.

Trailer lights generally fail due to corrosion. This occurs after the lights are submerged when you reverse the trailer into the water to launch or retrieve your vessel. Saltwater can quickly corrode the terminals to the point where they will not conduct the 12V power, which means that the light bulbs won’t work.

Many boaties solve this problem by using a light board, which is a removable set of trailer lights affixed to a board on the rear of the vessel. This can work well, but also means more setting up time at the ramp plus the increased possibility of breaking a light during removal and storage inside your vehicle.

A few years ago LED lights gained popularity in industrial, commercial and household usage due to their extreme brightness. They were much more noticeable than conventional globe lighting, durable and required only minimal maintenance.

However, LEDs were then very expensive so the boating fraternity persevered with conventional lights. Thankfully, in the last 12 months or so, the price of quality LED trailer and cabin lighting has dropped considerably, making them a sensible long-term, low-maintenance option.

Because the light mechanism is fully sealed, LED lights can be totally submerged without fear of corrosion or shorting out. These extra-bright lights greatly decrease the chance of a rear collision by a following motorist and the durability factor means they will always work.

Receiving just one fine for not having a roadworthy trailer can be more than the cost of a pair of quality LED trailer lights. They start at less than $150 per pair and are easy to install on your existing wiring. Different trailer designs and LED brands will require slightly different procedures, however the following steps will give you a general idea of how to install them yourself.

1. Although the internals of the unit are sealed, I like to add a little silicone around the entry point for the wires at the back of the unit to make it even more waterproof. The LED light will have two small drain holes on the bottom of the light for any water that does happen to enter the housing, but sealing the hole with silicone will prevent most of it. It’s not compulsory, but is a good idea in most cases.

2. Strip about 5-7mm of coating off each of the wires. Here, I use a special wire-stripping tool (about $8 from Bunnings) but any basic pair of scissors or cutters should do. On the driver’s side (right) you will generally need to use the brown, red, white and green wires from the conventional trailer cabling and on the passenger side you will need the brown, red, white and yellow wires stripped. Just cut the extra wire off on each side as you won’t need it.

3. Work out how you are going to mount the lights and their desired position. Mark out wherever the holes will need to be drilled to allow the screws to go through the mounting plate. You may find that one or more of the holes from your old trailer light mountings can be used, but it is not very likely.

4. Drill holes where you have marked, making sure the drill bit is slightly thicker than the mounting screw protruding from the back of the light. Check to make sure the LED light unit will actually mount in the desired position (just in case you stuffed up!).

5. Joining the two wires is best done with heat-shrink joiners (I use Quik-Crimp bsw2) as these create a totally waterproof connection. Use a crimping tool to fasten the wire inside the internal crimp in each joiner. Connect red to red, brown to brown and so on until all four wires of the same colour are fastened on each side. Then, you can connect the trailer to the car to guarantee that both blinkers and stoplights are working.

6. These joiners are heat shrinkable and have internal glue to fill any voids, making them totally waterproof. You will need to heat the joiners to make this work. A paint stripper gun is ideal but a hair dryer on its hottest setting or a cigarette lighter should also work.

7. The blue outer of the joiner will reduce around the internal crimp and wire. The glue will melt to fill any voids or small cuts left by the crimping tool.

8. The holes you drilled in the trailer will need to be covered in a lead-based product called Cold Gal, which is a cold galvanizing paint. This will prevent, or at least slow, the onset of rust. It seals the metal again to prevent salt water reaching it when the trailer is submerged. If you are lazy like me and hate washing paint brushes after use, then use an old toothbrush or cotton buds to apply the Cold Gal to the drilled area. Just throw them away after use. A couple of coats can be applied for increased protection.

9. Affix the LED light unit to the trailer mounting by fastening the screws. Use a nylock nut or a split washer to prevent the supplied nut from unscrewing with vibration. Use some loom tube (a split tubing available from chandlery stores) to cover any loose wiring and prevent nicks from stones or chafing against the trailer.

10. Use some zippy ties to secure the loose loom tubing close to the trailer body to avoid it accidentally catching on anything you may pass.

Your LED trailer lights are now ready for use and should provide many safe and hassle-free years of transport for your pride and joy!