trailer hitch wiring

I want to add additional backup lamps, just wondering if I can tap into the grey trailer harness behind the rear bumper(has never had trailer hooked up) and will everything work, or do I need additional fuses or relays to make the wires back there work. Any laws on adding extra lamps back there usually?


if anyone else planning on doing it check YOUR (not mine local laws

"Backup lamps
4.18 (1) A vehicle may be equipped with not more than 2 backup lamps, mounted on the rear of the vehicle, that are capable of displaying only white light to the rear of the vehicle.

(2) A backup lamp must illuminate only when the vehicle is in reverse gear.

[en. B.C. Reg. 476/98, s. 2.]" this is for BC canada

 

[MountaineerGreen]

Your factory trailer harness does not have a backup circuit in it. You will have to pull one of your tail lights and connect to one of the leads that goes to the reverse light bulbs. I would use a relay and separate power source to run additional lights.

 

[Turdle]

I moved this to the "towing" sub forum--

 

[Gatorblazer]

Not to argue with you MG but if you are using a low watt light just for back up lighting, and seeing as how they are used for a short period of time; there should not be a huge issue with running the lights with the stock lighting. If they were larger watt lights with an intended longer run time, then I would agree with you. If I'm wrong, please let me know since I intend to do the same thing as reserved50.

 

[reserved50]

I'll just see how many amps/watts the factory bulbs draw, if the ones I buy are over by about 25% im sure I have to do rewiring, or keep blowing fuses(I dont want to overload the wires)

 

[MountaineerGreen]

Well, depending on what you are hooking up, a relay/additional power supply may not be needed. If say, you are going to use two 55 watt lights, I would say a relay would be a must.

It wouldn't be that difficult to run a 10 ga wire from the battery to the back, just run it along the frame rail. I ran an oversized wire for my small amp some time back, have since added a distribution block and now use it for my 12v source on my RV plug.

 

[Gatorblazer]

The reason it would be nice to power it from the rear lights is the convienence of it. It would be nuisance to have to flip a switch every time you wanted to back up. especially out here in the middle of dark no where. The question is would adding the 55wt lights (I think those are the lowest watt you can get for aux lighting) enough to burn the wires? I would think not.....but then Ive been wrong before on a Tuesday

Reserved, have you looked for a halogen or brighter replacement bulb? I cant find one for a first gen, and havent looked for my 2nd gen.

 

[MountaineerGreen]

I suggested wiring in a relay, you could wire it to automatically come on when your regular reverse lights do- no switches needed.

You'd be surprised how small some of the factory wires are, I would be cautious about adding more strain to them.

I can work up a diagram if interested for a standard relay.

 

[Gatorblazer]

Could you please? I think reserved might want one too. Sorry if I hijacked it from you buddy.

 

[MountaineerGreen]

Using the diagram, which represents most any standard automotive relay-

Post 30 would be hot lead from battery (fused of course)
Post 86 is +12v from the reverse light wire
Post 85 is -12v (ground) just ground it to the body
Post 87 goes to the lights

Wired like that, when you put your truck in reverse, the lights come on, take it out they go off. No switches needed.

This page explains it well-

http://www.the12volt.com/relays/relays.asp

 

[reserved50]

nah I just wondered if there were any reverse wires in the trailer harness. Just means more work for me now since there arent any, I just remembered I have 8gauge wiring to the amplifiers under the rear seat if I need a power source lol. They do sell 35 watt fog lamps but Im sure they will blow a fuse(think each reverse bulb is rated half that). Need the extra lighting due to the limo tint I have over the factory tint and for the rear-view camera I added(colour cameras need more light, oops)

 

[Gatorblazer]

Try finding an aftermarket bulb replacement. Might work for you

Thank you MG

 

[reserved50]

http://bulbster.com/zcart/index.php?main_page=product_info&products_id=2388


I think just a bulb replacement wont work, the diffused lens and reflector of the tail-lamps scatters and dims the light quite a bit. Since they say the factory wattage is 27, which is about the 25% higher than 35 ,I'll chance it and just give it a shot, the 35 watt bulbs will draw about 6amps, I'll just see what else is on the same circuit...but the relay is the safest bet and prevents wires from heating and corroding leading to further electrical prolems , ha