in january i bought a brand new '06 18' car trailer, all the wiring was hooked up just needed to wire up the connector to plug into my truck. i didnt feel like hooking up a 7 point so i just wired up a 4 flat and bought an adaptor to plug into the 7 point plug in on my truck. i had no problems with this up til last weekend when my right turn signal didnt work, i figured it was bad wiring since i threw it together pretty quick when i did it the first time so i cut the 4 flat connector off and checked my trucks plug in with a test light, everything worked, then wired up the 7 point connector on my trailer so i can use my trailer brakes, nothing at all worked, i could ground the test light to my bumper and stick the test light in all the wires and it showed power to them but if i grounded it to the trailer i got nothing. i then took the lights off and realized my problem was just a bad bulb so i replaced both left and right tail lights, and rechecked this time my left turn signal worked but the right turn signal made both lights flash so i said screw it and cut the 7 point off and wired the 4 flat back up, same result. i dont understand whats causing this, i matched the 3 colors up exactly how it supposed to be and im not color blind. any ideas?

 

Ground

Bad ground on either the trailer or truck .
Make sure the ground is good and clean and goes to the frame.

 

got the 7 point hooked back up pretty much same result, left turn signal works, right turn signal makes both lights flash and running lights dont work. i double checked the ground which is fine, metal cleaned and bolted to the tongue of the trailer. about to give up on it and see if theres somewhere i can take it and pay to get it fixed. what am i doing wrong?

 

Are you sure the right turn signal isn't connected to the running lights by mistake?
If the left signal light is working, then the right signal flashing both lights
can't be the turn signals, or the left turn signal would flash both also.

Here's a couple web sites with wiring info:

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

http://www.etrailer.com/faq/wiring.asp

You need a probe with an indicator bulb or multimeter to troubleshoot effectively.

 

Be sure the lights themselves are also properly grounded.
If the lights are dimmer when both flash, it is probably feeding back somewhere due to a poor ground.

 

Rebel -

Did you ever get that car trailer wiring working correctly? Sure hope so, 'cause I think Illinois would like you to have working brakes on a trailer that grosses over 3000#. Let us know what the problem was.

Steve

 

lights still do not work correctly.

just today i replaced the whole light assembly both left and right, on the old ones there were some contacts blown inside on them. hooked all the wiring back up checked the turn signals, both work the way they're supposed to so im thinking "yes, finally", go to check the running lights- nothing "$%^$%-*$%&*" so i get the test light out check my truck and it says nothing, get under the hood and theres a blown fuse for trailer park lights, replace it and go to check the lights again but nothing, fuse blew again, i checked to see if the wiring was right and its not, the ground and brown wire were backwards, fixed them, replaced fuse again, so everything should work, check the lights and still nothing, i grounded the test light to the same place as my ground wire and my truck plug in shows everything working but when i plug the trailer in and stick the test light in the brown wire i got nothing. both bulbs are good, turn signals work but no running lights. any other ideas?

 

Try grounding the trailer to the truck by using one side of a pair of jumper cables. Clamp one end to the truck frame and the other to the trailer frame, then you know you have a good ground. You could also try using a battery and ground it to the trailer and feed the positive to the running lights to see if they work (make sure it is not plugged into the truck if you do this).

Just a thought.

On a side note, I pulled my camper with my screw for the first time this past weekend and kept having problems with lights and brakes. After I got home while I was trying to find out what was wrong, I reached up behind the 7 pin connector on the truck and the back side dis-connected in my hand. I plugged it back in and everything worked fine. I don't know if it is supposed to come apart or not but it did. I am going to have the dealer check it when it goes in for some warranty work.

 

Did you install the wires inside the trailer plug, or did the plug have pigtails that you spliced into the trailer wiring? If it's the latter, the factory might not have made a connection between the pigtail and pin.

Steve

 

I agree with the grounding issue. 9 out of 10 times I've found a bad ground causing messed up lights. Sand your ground points, no rust or paint. The jumper cable from a known good ground on the truck to the trailer is a good judgement of a the problem. Good luck to ya - who knows - maybe its already fixed.