2002 xlt trailer light dont work. just got the truck and it did not come with an owners manual.it has the tow package with both plugs but neither work.any ideas where i can get a shcematic for the fuses. any idea will help. thanx

 

I found on my 98 that the factory plug contacts rotted out. Check this too

 

It should use the same fuses as your vehicle lights. Except under the hood I belive there is a master fuse for the tow package. Location should be in the owners manual.
Make sure the lights on the trailer work and make sure they have good ground both threw the plug and to the trailer chasis plus through the ball. Sometimes if I park a trailer very long the lights wont work untill I've pulled it a little ways and work the rust off the ball coupler. Is this a four wire flat or 6 wire round plug on the trailer? Have you put a multi meter on both of the plugs on the truck or tried both plugs?

 

I'm curious. Just started recently,all my truck lights work but when I plug in either of my trailers just the left brake/turn light doesn't work. I'm wondering if there isn't a relay of some sort for that.

Anyway, there is some relay that come with the harness assembly when the truck is new that needs to be installed in power box under the hood, but I never installed them until I put on a brake controller/harness assy. I had lights on my small trl prior to it so I doubt that would be your problem.

 

Both brake light for both left and right sides runs of the same single wire. So if neither of the left brake lights work on either of the trailers and the right ones do. Then I would suspect it's just a coincidence. Likely either the bulbs are burnt out or the light assemblys are not getting a good ground. Or one is one and the other is the other, I would check those two things on them first.

 

check in the glove box, center console and under the center console cup holders for the controler harness and relays with the instruction sheet. If you dont have it then this post may help.

 

In the power network box under the hood, check fuse #20. #19 is the right turn signals and stop tail and #20 is the left. should be a 10amp fuse.

 

In the under hood fuse box drivers side of truck there is a 10 amp fuse for the left turnsignal and a seperate fuse 10 amp for the right turnsignal these are numbered 19 and 20
trailor tow running lts go through a relay and are fused by a 20 amp fuse numer 5 Battery charge and backup lights are handled by relays.

 

Guys am I wrong? He said that neither the left brake nor the left turn work on them... As far as I know there is not a left brake fuse and right brake fuse. Nor sperate left brake relay or right brake relay. There is only one circuit for the brake lights. If the right brake light works then the left will be getting power too and visa versa. Correct? So as he describes it then it can only be a certain number of things. (IE either Bulb, ground, or connection to that lamp.) Right?

 

You are wrong.
The trailer lights are seperate from side to side. Fuse # 19 feeds the right turn, stop and tail lights and #20 feeds the left turn, stop and tail.

 

There is no such thing as brake lights. brake lights are a combination of left and right turn signals not flashing. this uses the bright fillament of the bulb. the running lights are the dimmer fillament and controled seperatly. In the flat plug you have four wires ground, usualy white wire ,running lights usualy brown wire, left turn yellow wire, right turn green wire. In the big conector you also have battery feed back up lt and traler brake control.

 

When I replaced the 4 wire flat (that came on the truck when I bought it) with a six prong round plug there was only 4 wires... Not trying to be a smart a$$ but hince the name 4 wire flat..

1. Ground
2. Tail lights/Brake lights
3. Left turn
4. Right turn

I then added a trailer brake control and an accessory constant power for the work lights and the one trailer I sometimes borrow that has a winch.

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

 

Most of the trucks come with the 7 pin round connector and they use the 4 flat adapter. This is what i assume you had.

 

Download a manual for free from here.