reverse/flood lights

[sardoghauler]

Ok guys i need electrical help here



Keep i mind when you respond that I'm not exactly an electrical whiz-kid



I want to add a set of lights to the back of a trailer that will double as reverse lights while backing and also be switchable from inside the trailer to use as area flood lights. The trailer has a 12v supply backed up by a generator for operation when separated from the tow vehicle.



How do I do it. It already has reverse lights so what do I do to make this system function? Would I be better off with 2 sets? I'd prefer one set that does both functions.

TIA



Craig

 

[TowPro]

I had 2 trapoziod tractor lights (tractor supply) mounted on the frame on the back of the last camper. They were under the camper, but they projected light rearward real nice for backing up. Because they were under the camper they did not shine up bad enough to bother others camping near where I was backing in.



I ran a red wire from the battery (with a fuse in it) back to a switch I had mounted in the back corner on the frame. From the switch I ran the wire to each light. For light ground I just connected the ground wire to where the light was mounted to the frame.



the switch was also under the camper, but on the Terry you could reach in from the back corner and get to the switch. The switch was one of those big plastic ones that lights up you can get at radio shack. No problems finding it because the "lever" part of the switch was around 2" long.



If you want to use wires that follow RV color code, Black is positive, white is negitive.



I would not hook them to the backup lights. Many times I used to turn the lights on after I was unhooked when working around the back of the camper.

 

[terrywerm]

There are quite a few things to consider here, such as how much amperage your lights will draw, etc. before a person could decide on the best way to approach this. If your lights draw too much current, the backup light circuit on the tow vehicle will never hold up.



The best bet may be to put in a manual switch on the trailer, then also add a relay so that they could be triggered by the backup lights on your tow vehicle. Adding another manual switch to the backup lights on your TV could be done also.



I'll draw it up tonight when I get home and post it here. I'll do my best to draw it up in a manner that just about anybody should be able to follow (I hope... . )

 

[Ramtough]

If your trailer has factory backup lights, you're in luck. Tap the wire going to the factory backup lights to energize a relay that will switch on 12v power that will be wired directly from the trailer's battery. Make sure you find a good ground or run a ground wire from the RV battery.



for your inside switch, run another wire from the 12V souce through the switch to the relay. I set my white night system up like this. Then either the reverse circuit on trailer or the switch can energize the relay. The relay will eliminate the possiblity of overloading the rv's electrical system.



finally, it is a good idea to put a resistor in the line from the backup light circuit to the relay. This will prevent the relay from back feeding electricity to the rv's reverse circuit when the lights are turned on via the switch.



If you do not have factory backup lights on the trailer, you are going to have to start at the tow vehicle and wire through the pig- tail to the trailer to get a reverse light to the back of the trailer. You should be able to tap the reverse line near the backup lights on the tow vehicle



Good luck & happy wiring.

 

[Prairie Dog]

Your trucks factory trailer wiring has no problem supporting a couple of 55 watt lights ~ it's built to do what your doing. It would be best to connect to the center pin of your factory 7 pin trailer connector. You won't need a relay and I believe it's even fused separately from the trucks other circuits so you don't even need another fuse.



Good luck,

Scottyi

 

[terrywerm]

I promised a drawing of the wiring schematic, and the one shown here is the way I have mine set up. First, the wiring in the pickup. When I am backing my fiver in the dark, it does me no good to have the backup lights come on on the pickup. The glare of the light reflecting off of the front of the trailer just makes it that much harder to see behind the trailer, so the DPDT switch allows me to select the backup lights on the pickup or on the trailer, but not both at the same time. When I put the truck in reverse, the backup lights will work on the selected vehicle. I also added a SPST switch so that I can turn the selected lights on from the pickup without putting it in reverse.

 

[terrywerm]

Now for the trailer wiring. There is both a switch on the trailer so that I can turn the lights on manually from there, and there is a relay for activating the lights from the tow vehicle. The main purpose of the relay is to isolate the trailer from the tow vehicle, IE: it prevents the lights on the trailer from backfeeding the tow vehicle when the lights are turned on manually from the trailer. The hard part might be finding an adequate switch, finding one to handle ten amps DC can be difficult, but they are available if you look around. Most auto stores carry them. Above all, make sure that you fuse the circuit!



I could have most likely left out the manual switch on the trailer... . I've never used it! If the switch was left out, the relay would not be needed and the center wire from the trailer plug could connect directly to the trailer's backup lights.

 

[Ramtough]

Prairie Dog - 2 X 55 watts at 12 vdc = 9. 2 amps. Do you really think the reverse light wiring is up to that with the loads for the truck & trailer? I'm standing by my original recommendation - relay. Less load on the truck and more reliable.

 

[Ramtough]

Terrywerm - Your diagram is straight forward. I did esentially the same thing when I installed a white night system on my truck. The problem I had was that when I closed the SPST switch, current was backfed into the truck's wiring and caused fuses to blow and all manner of other strange things to happen. Diodes in the line between the reverse switch and the DPDT switch solved the problem.



The nicest thing about the SPST switch is the freedom it gives you to return the favor to every idiot who comes up behind me with his bright lights on - I love it. It will also cause tailgaters to drop back, daylight or dark. In my opinion, this is a very valuable safety feature for that reason.

 

[TRCM]

My factory wiring has the center pin wired for b/u lights. All I did was put lights on the trailer, and feed them from the center pin.



Just add a switch to give it a seperate power source, and you have what you want. Just make sure when the switch is in the off position, that the backup lights will still work. To do this, you will need a relay, or else the trucks b/u lights will come on when you turn on the trailer b/u lights for general lighting.