Can Utility Lights in Trailer Run Off Running Light Circuit Through a Switch on an Aluminum Trailer

Updated 04/04/2016 | Published 04/01/2016

Question:

I recently purchased a triton enclosed snowmobile trailer. The previous owner installed interior self grounded, single wire utility lights you see on tractors. those lights are then connected to a toggle switch, but the wire leaving the switch isnt connected to anything. He was going to connect it to a battery but never did. 1 Can I run that wire to a clearance light? 2 do I have to worry about the light being mounted to the aluminum frame if its self grounded through the hardware? If so how would I ground the light properly? 3 would you recommend adding a fuse between the switch and power? Thanks

asked by: David

Expert Reply:

Yes, you can run the switch power wire to a clearance light but the trailer would have to be connected to the vehicle with the running lights on for the interior lights to have power.

Aluminum does not offer the best ground so if the lights do not work you may have to run a jumper ground wire to a steel component or the main trailer connector ground. I would try it first to see if there is any problem with grounding to the aluminum surface.

A fuse is not needed though you could add one if you want to. What might happen is the power draw on the running light circuit could be overloaded when you turn those utility lights on. It just depends on how much total power draw there will be and how much the tow package on the tow vehicle is rated for.

Ideally, if the truck and trailer both have a 12 volt power circuit you would run the power wire from the switch to that circuit. If not then a battery mounted on or in the trailer is the way to go.

expert reply by: Michael H