Trailer Hook Up

[natertot]

I just recently acquired a small little trailer from a fellow WSF forum member and I am in the process of getting it road worthy. I am 90% of the way there. I got the registration for my state figured out and it is now plated. I got the ball set up for the hitch receiver and locks to put on it so the trailer can't be removed from the car without keys. Now I am down to the lights.

The trailer has the basic flat four connection so I got the basic flat four connector for the car. I hooked everything up, tracing wires and routing the new ones. The tail lights, both turn signals, and hazards are good to go. No brake lights on the trailer though.

Did some more digging around the car, chasing more wires and discovered that the brake lights are on its own separate deal from the tail lights.

My thought is that I need to uninstall the flat four connector on the vehicle and install the round six connector in its place. After that I should be able to use an adapter bringing the six to a four and have all the lights on the trailer work.

Am I correct in this logic?

[crashdive123]

IIRC (been a while since I wired a trailer) the brake lights are wired on the same pin as the left and right turn signals (trailer side). I don't remember for sure, but I don't think it matters how many pins are on the connectors. Check with your manufacturer (dealer) or the local U Haul rental and see if they have connectors specifically for your vehicle.

[Rick]

Crash is correct. Hope this helps.

http://www.accessconnect.com/trailer_wiring_diagram.htm

[hunter63]

Now THAT is the best diagram I have ever seen.

Good luck Nate.....My three most hated thing are that are a PITA...... Trailer lights, post hole diggers and proctoscopes..... and not always in that order

[kyratshooter]

Newer model vehicles are a pain to wire to a trailer.

If Candice and the kids need anything after you have the nervous breakdown tell them to give me a call.

[hunter63]

New vechicals won't even give you a wiring diagram.......or tell you what the fuses are for.

Found that out by blowing a fuse in my trailer lights on "Big Red"...and took a guy on here that snuck me the OEM diagram and fuse chart.
Luckily both truck have the tow package, so were already wired.

Most problem on trailer lights are a "Bad ground"....keep that in mind.

[kyratshooter]

I just ran and looked at mine again and it is just as Crash stated, the brake lights and turn signals are wired to the same pin.

Used to be you could splice into the wiring in the vehicle with safety pins and make a trailer work. Those days are gone.

Many of the newer vehicles have the current controlled by the computer to the point that it allocates only enough voltage to the light to run the specified LED. When you hook a trailer up and splice the wiring in the computer shuts off the circuit because it is drawing too much current.

The last one I had wired required a power lead be wired directly from the battery to the trailer connector and bypassed the power from the vehicle circuits entirely.

[natertot]

Okay, I found a solution to the issue, cost was $25 and an hour of time.

I left the trailer lights alone, that way they could be hooked up to a vehicle that has a good four pin connector. The four pin connector on my car I also left alone, running tail lights and the turn signals. I went out and bought a set of bright red lights and installed them on either side of the trailer in addition to the other lights. I then ran their wiring up to the tongue of the trailer and installed a two pin connector, one for the left and one for the right. I then hooked up the opposing two pin connector to the car, running a wire to the left and right brake lights.

To use the trailer on my car, I have to plug in two connectors to have all the required lights. If I hook up the trailer to any other vehicle that has a true four pin connector, then I just plug in the one and I am still good to go.

It is a little "redneck engineered", but it works and I get no tickets!

[crashdive123]

.......and you are less likely to get rear ended.

Well done.

[hunter63]

Good example or alternate thinking.....
Congrats.

Had a tow bar....metal bar with all the lights, made to attach to the back if a towed car (my race car at the time).........had to add a separate ground wire to the metal bar, as the suction cups were rubber and the vehicle's metal could act as the ground.

Gave a trailer to my SIL, he replaced the decking on it....bolted the light brackets to the 2X 6 he was using for a frame.
Couldn't figure out why the lights were flashing all sorts of ways......They were not grounded properly...and were ground back thru the other circuits.

So if the back of the trailer looks like a juke box....it's a bad ground.......white wire...corrosion on connections.