Trailer wiring problem

[Steve]

I have two wires coming from each of two of my rear trailer lights. Then there is one ground wire that connects to the trailer. So in all there are 5 wires coming from my trailer. Since I can't find any flat 4 prong/5 wire plugs to plug into my 4 wire/4 prong flat plug on my blazer what can I do? Is there a way to reduce the wires coming from my trailer to only 4? Thanks for any help, Steve

[Redskin]

Trailers utilize a four wire system. The ground (1) , a common power for braking/healights(2) and a blinker for each side (3&4). the common power wire goes to each tail light, (and connects with one of the tail light wires.) It would also power any of the marker lights on the sides of the trailer. The second wire coming out of the lights is "dedicated" to that side. I've rewired trailers using a 3 wire orange utility extension cord and added a fourth wire to ground between the trailer and the vehicle. Hope this answers your question.

[EricCO]

My lights ground to my trailer. The trailer gounds to my vehicle when I hook it up. The ground wire on the trailer hookup is not connected to anything. It works for me.

[Redskin]

That can work as long as you have a good connection between the trailer and vehicle. When the ball or hitch get corroded, that ground can fail, creating a problem: " they worked fine last time...." I solved it with a separate ground connection between trailer and vehicle. This would be unnecessary if you use your trailer enough to control the corrosion (lucky you)...

[EricCO]

I periodically scrape and clean the ball and hitch to avoid the problem, but if I connect the ground wire to my trailer will I blow fuses? Will it be double grounded (if there is such a thing)?

[Redskin]

No - I've been doing the wire ground thing for 15 years. It has eliminated the problem of lights not working for "no reason" or only one side working etc. I have never had a fuse blow because of it.....I'm not an electrician, but my understanding is either you're grounded or you're not....

[ford nut]

You should have 4 wires from your trailer (minus brake wires). As per code
Brown-run & markers
Green-right turn & brake
Yellow- left turn & brake
ground-which should be done properly, not thur hitch

[SteveW]

How would you suggest doing the grounding? As of right now I have the ground wire attached to the trailer below the which. I worked on it tonight and my right side works perfectly, but the most my right side will do is go halfway on, withought the side markers.

[Tom]

Steve let me get this straight, The right trun and break barely work and will not go on if the headlites are on ? Let me know the exact symptom and I'll help Tom

[walleyedm]

Are you sure that your trailer does not have brakes? the 5 wire harness is usually for trailers with brakes , it's used to turn off the brakes when backing ><(((((('>

[twogun]

Sounds like you do have a bad ground. no rusty wire i hope. you've got the service(hot) wire mixed with something ethier on vehicle or trailer or both. Clean all wires good and use butt conecters. How old are your lights? is the light elements rusty? If you don't have trailer brakes go to a flat four plug. Do you have a heavy duty flasher? They just plug in where old one is.(under the dash) good luck...

[Steve W]

Hi Steve, nice handle!! What you are dealing with is a ground problem; your ground is backfeeding through one of the wires that are supposed to carry current to the lights. The most common cause I've seen for your problem is a corroded tongue on the trailer. If the tounge can be slid for adjustment or is bolted to the frame it can corrode and not conduct current from the back half of the trailer. Look at the area where the tongue meets the frame (this will be several feet back from the front of the trailer) to see if this may be the case. If it is welded, it isn't the problem. You can also test it by clipping a wire onto the front of the trailer and running it back to the rear to carry the ground.

If this is your problem, simply attach a jumper wire from the tongue to the frame and the problem will be solved.

If this isn't the problem, then you need to clean up all ground contacts for the lights. Take them off and wire brush the contact areas to get a good ground.

I don't mean to write a novel, but I'm trying to explain it without confusing you to much. If you need more help just ask or send me an e-mail.

Good Luck,
Steve W.