Adding backup lights, Wiring help needed.

Safety lights fall under US DOT regulations so it behooves one to check with them first before adding such lights.

This may void your safety inspection...

Only certain lights can be on the rear and front of towed units...

You might get away putting them on the sides up high to the rear of the trailer...

What you don't want is invest some monies into these kinds of lights only to have to remove them when it becomes inspection time. Talk to the JEEPS guys in California about adding lights...

Not saying it can't be done but one should check on the requirements first. Even the lens of these light have to have DOT stamp approval numbers on them...

Just saying...

Roy Ken

Positive to switch, switch to 85, 86 to ground. Positive to 30, 87 to load.

And leave 87a alone. But, the switch won't keep the lights on after you disconnect the umbilical. For them to stay on after unhitching, you need a 12v hot to a switch to the lights that does not run through the relay, OR, a 12v hot to a switch to the relay on 85 when you are unhooked.

However, your best solution is to forget the umbilical and a relay completely. Run from the trailer battery for a 12v hot to a switch to the lights. When you need them on, get out of the truck and hit the switch. When you are done, hit the switch again.

sfpcservice wrote:
Positive to switch, switch to 85, 86 to ground. Positive to 30, 87 to load.

Where does the wire from pin 7 connect?

I would assume it goes to the switch then to the relay leg 85?

The same goes for the positive wire from the battery, to the switch then to leg 30 correct?

As far as the switch goes, what I am going to use is a SPDT (Single pole double throw) marine grade toggle switch. It powers 1 of 2 circuits at a time (REV on, off, TT battery on) in order to be able to turn the lights on with the truck out of reverse.

Thanks, Lee

You absolutely want a relay to control the lights. I did not see if you posted the size of the lights you plan to add. If they are smaller lights plan on at least 1 amp per light. The problem I see with your plan is adding front lights to the trailer. Backup lights point backward. You would have to check your state laws on adding forward facing "backup" lights.

Some relays have two separate triggers. One of them would be required to activate the lights. The Diodes allow one way voltage. Expect the diode to drop the voltage by .5volts. Wire the diodes on the trigger or control side of the relay. This allows maximum voltage to the lights. Be sure to fuse the power. I would add a fuse before the relay. If your two lights draw 1amp each, use a 5amp fuse for two light protection.

I would add two separate circuits. One wired to the truck for rear facing backup lights. Another separate circuit for forward facing clearance lights. Have you considered a wireless remote control system? Not expensive to purchase. Have the rear facing backup lights wired to the truck and the wireless system. Either could engage the lights. Wireless switch #2 to the forward facing clearance lights. If you have extra wireless control circuits use #3 to control clearance lights under the stairs. Have #3 lights pointed downward to avoid glare. As you approach the trailer at night you could click on #3. Circuit #4 could point to some dark blind spot?

Don't use expensive lights. Do buy an extra for replacement. This allows the future replacement to match the current lights. I use Kawell lights from Amazon. They are cheap and easily replaced. No idea if they are the best. They have worked for me. I also included a video of my Dodge. The lights are a combo of the included link and another style from the same manufacturer. I have many of these lights on my offroad Jeep.



Kawell from Amazon




My towrig clearance lights.

WCJEEP, all lights will be facing to the rear / outward & if at all possible they will be mounted up underneath the TT.

Thanks for the info on the diodes, do you think I need one on the 7 pin leg or just the one on the battery leg??

I like those Kawell lights, nice & inexpensive plus their waterproof. I'm planning on adding a set to my boat trailer & those should work out nicely.

I would place the diodes to protect the truck wiring harness. Also place a diode between the second trigger (switch) and the relay. I would not place a diode on the actual supply to the lights. The diodes protect the switch and truck harness where slight voltage drop is acceptable. Do not place a diode on the high(er) amperage feed from battery thru relay to the lights.



Edit: there are very specific laws regarding vehicle lighting. Placing backup lights to point outward would probably be a violation. I had a long uncomfortable conversation with an officer while using offroad lighting on my Jeep on the beach. The beach is considered a state highway. I didn't receive a ticket even though I was in the wrong. Didn't know I was in the wrong previous to our conversation.

I use my Dodge and Jeep supplemental lighting off road or in the RV park while setting up. I avoid using supplemental lighting on the pavement. I try to avoid uncomfortable talks with law enforcement. Your laws probably vary.

Why have a relay at all, when you disconnect the truck plug in a spare plug with a jumper from the hot to the yellow lead. Unplug and stow when you have finished setup.

The reasoning behind having it setup both ways is, when I'm backing into a campsite, I usually have the little woman guide me in, then I'll get out & see how many boards I'll need under which wheels to get the TT level, I'll layout how many boards & where, then I'll pull forward & my wife sets the boards in place, then I backup the TT onto the boards.

Every time I take the truck out of reverse my lights would go off, leaving my wife & I in the dark to do a simple job, but now she's holding the flashlight (& shining it everywhere I don't need it) & I'm working in the dark.

Now if it was wired up the way I want it, as soon as she gets out to guide me in, she can just flip the switch & we have lights on as long as we need them.

Now 9 times out of 10 we get home & it's dark & I have to back my 27' TT 300 + feet down my very dark narrow & switchback driveway, the wife usually doesn't need to help me til I get it near the house where I have to thread the needle between the giant oak tree & my 18' pontoon boat that resides next to my TT.

Lee

Jeez what is it with Virginia and George Orwell grade vehicle inspections? They need to send those boys down here and see what REAL anarchy is. Like the one and only time I drove on Vancouver Island. State troopers pulled a gut over for doing 95 in a 90 zone. Another blue car clocked me for a kilometer with my speeometer glued to 90. Micro management. When common sense meets failed lawyer regulatory and revenue generation. Grumble. Grumble.