I would like to know how some of you are hooking up aux. lights to the backup light curcuit. Do I need to have a relay?

I've got a set of 55 Watt driving lights and I want to hook them to the reverse light switch... Is this right or wrong?

 

I use PIAA 40 fog lights in my Reunel bumper. They provide a nice wash of light behind me while backing up. The light themselves present too great a load to run directly off the backup lighting circuit. What I did was to to energize the coil of a 40 amp relay by the backup light wires, and power the light from the 12Volt constant on the trailer hitch wiring. Please take this advice from someone who learned the hard way. Solder all connections, don't use Scotchloks, and most importantly stow the relay and splices in the tail light housing. If you're in a salt area, the connections will last exactly 1 winter storm before they corrode and break off if you leave them exposed to salt spray. My first try had the connetions and relay up behind the spare, in the bumper cavity. Bad move! The 12V constant splice must be made down below, but after soldering, I RTV'ed the joint to seal it from corrosion. You can purchase relays and sockets with leads from Parts Express for a few dollars. I potted the entire relay in RTV to protect it from the salt baths our roads receive up here.

 

As Commatoze said, you'll definitely want a relay for any lights that add enough illumination to be worth the work of installing them.
I don't get the kind of weather those NE fellas do, so my relay is screwed to the bottom of the rear bed mount, all my wires have spade connectors crimped on, and all I did was coat the wire ends with dielectric grease before crimping. 2 years now with no problems.

 

I used a dash mounted switch and a relay can turn lights on and off and dont have to be in reverse.

 

On the old hunting truck ( 87 Dodge Dakota 4X4), I used a off road light relay. I ran 1 wire with a inline fuse from the battery to the relay, and 1 wire from the frame of the truck to relay. Next I just wired the extra lights to the relay. To finish it off I tapped into the backup light wiring and ran it to the relay. The off road light relay draws less then 1 amp from the backup light to open the relay. I have been using this setup for 2 years with no problems.

 

Thats not necessarily legal in a number of places...usually rear lights must be tied into the trucks reverse lights.

 

I mounted my relays for the reverse under the hood- 12V from the PDC, relais, switched by the transmission reverse sense switch. From there on a nice fat cable to the back, silicone where it enters the light and voila- no corrosion problem since all the connectors are high and dry, the fuses are accessible etc.

AlpineRAM