bought some new lights for my trailer. older model, put new wiring on and can not get them to work. put the old lights back on and they work great with new harness. anyone know what im doing wrong. thanks
Is the trailer hooked up to the ball when you tested the lights? Dominick
Sometimes new style lights have plastic housings & may require a ground wire.
yes it was hooked up to ball. yes it is a plastic house and I do have a metal washer and ground wire connected. thanks
Best thing to do is run a separate ground from each light up to the tongue. You will never have a problem.
Quote from: handi2 on July 05, 2017, 10:44:11 PM
Best thing to do is run a separate ground from each light up to the tongue. You will never have a problem.
No expert, but have wired a few trailers -- 2 last year.
Had trouble with one -- so just ran an extra ground from each light back to the tongue -- then so as to not rely on the ball as ground -- jumped the ground through the pigtails -- all worked fine. Since I pull multiple trailers -- I use a 7 prong on my vehicle -- coupled with an adapter that goes to a flat 4 on the boat, utility trailer, or kayak trailer.
Here is a cheap hint -- if it is a hassle, just take it to your local U-Haul. For about $35 labor plus any parts -- you will be done. These guys wire more trailers in a day -- then 10 of us wire in a lifetime.
Vest,
Fred
let me get this straight run a ground wire from each rear tail light back to tonge and ground it. thanks for your help.
FYI, I asked at Uhaul about doing my truck lights for my small Gregor trailer.
I asked specifically if they use the squeeze on crimp connectors to add plug assemblies, to which they replied yes. I passed.
I work everyday with landscape lighting and irrigation wiring and see how that type of connection goes bad rather quickly. Then you hear the 'It works if I jiggle the wires' comment.
I will be doing my own, just haven't figured out the layout yet. My old Mazda has a bit different wiring.
When wiring for a trailer (especially marine) I prefer to solder all my connections then coat them with liquid electrical tape or something to seal them up real good.
As far as grounds go...they are extremely important. An automotive electrician once told me, "It's ALWAYS the ground." and he was correct 99% of the time. With that said; you can ground the lights to the trailer chassis but use something like Lectra-Shield on the connections. (https://www.crcindustries.com.au/products/corrosion-protection-and-inhibitors/lectra-shield-electrical-protection)
Make certain to use a 4-way connector with a dedicated ground instead of relying on the ball. (http://www.curtmfg.com/Category/224/4-Way%20Connectors) Typically you will have four wires at the connector. On the truck end the three female connectors will be left+stop, right+stop, running and the male will be ground. The brake lights are shared on the right and left turn signal wires. ALWAYS unplug the harness and secure the connectors in a high location before submerging in saltwater as saltwater and current are no bueno for your connectors. The trailer side is okay if it gets wet as there will be no current. This is also why you put the connector with three male and one female on the trailer side...it's easier to keep clean. Be sure to was it with fresh water before plugging it back together.
Your Mazda may require diodes (many imports do). You might be able to find a dedicated plug-in harness adapter or you might need to just get some diodes from Radio Shack and solder them into your trailer harness on the truck side. The diodes will only allow current to pass in one direction. I don't recall all the details as I only had to do this once on an import but I don't remember which circuits required isolation. Google will have the answers you need but first search for a plug-in solution. (http://www.starautoaccessories.com/towing5.jpg)
Good luck
Mike
Question what trailer lights are you using , leds or incandescent bulb . Is the wire harness 18 -22 gage wire ,harbor freight special ?
Most of the new wire harness have a lot of tin mix wire and rot real quick around salt water . I use 12 -14 gage wire extension cords . 1 run down each side , this way you have a good ground wire to work with for each tail light . Slide heat shrink tube on make connections and shrink . Side marker lights i run separate wire for them . All connections are made at the tongue . I also use a small 12 volt battery and old pig tail to test with , this take the vehicle out of the equation . A 12 volt test light is your friend also . joe
Standard 4 wire trailer schematic