weird trailer light problem

[bar79lee]

Hey guys,  I have a new trailer and 14' jon boat,  and the trailer lights where hooked up by academy, to the ground posts of the lights.  My mom went and picked up the trailer  and it blew her fuses,  i then re wired them the correct way and they worked fine.  The other day i was taking the boat with me and for some reason the ground wire became disconnected from the trailer,  and when i stopped to put gas, i checked and then reconnected it.  now the only lights that come on r the parking lights.  the blinkers, hazards or brakes wont come on.  i've checked the voltage coming from the truck and it shows that my 2 brake and blinkers have a constant voltage and the constant wire shows nothing, no matter what lights are flashing or on/ off.  if i turn the parking lights off the lights go off and when i turn them on, they come on,  other than that i can't figure it out.  im guessing that i somehow pulled the wires tight at some point causing the ground to come loose, but what would cause it to do what its doing now

[fishhawk]

I'm assuming your truck to trailer connector is a flat 4 wire, if so disconnect it and with a test light with the ground wire clipped to the one small protruding post at one end of the plug on the truck, this is the ground. Turn on the park lights and touch the probe to the hole next over from the ground post, it should stay lit constantly. touch it to the other two and nothing should happen. Now with the park lights still on turn on the left turn signal, touch the hole next to the ground again should still be constant power. Go to the next hole over and the light should blink, third hole should be nothing. Now turn the signals to right with parks still on,same routine, first constant, second nothing, third blinking. Now turnoff the signal only, leave on the parks and have someone hold the brake pedal down., All three holes should have constant power. This is enough to get you started. If your plug is different there should be corresponding wires that match the signals in each test above. Any questions or if it checks ok we need to move to the trailer wiring next, post your results I"ll try to keep tabs for your response to get this fixed quick. I know this is alot of steps but one bad reading could be the clue to the answer.  

[bar79lee]

Thanks hawk,  i've already tried that ,  and i do have constant next to the ground( constant wire)  but no matter what sequence i put the lights on, flashers, blinkers or brakes,  i get no response from the other two.  im not sure but i checked the fuse to see if it would blink or anything and it doesn't.  it is a 2006 ram 1500,  do u know of any other fuses or connectors that i might be able to check.  i checked as far up the trucks trailer pig tail as i could see.  

[fishhawk]

Are the lights on the back of the truck working when you use the turns or brakes even if the trailer is not plugged in?

[bar79lee]

yes,  the truck lights are working fine.  its almost as if theres a bad connection,  but how that could be,  i don't know.  like i said ,  it was working fine,  and every since the ground wire became disconnected,  they don't work.  

[bar79lee]

i was thinking that it blew the fuse when it became ungrounded but being attached to the truck shouldn't have caused that,  im thinking it might be something with the computer,  so i've disconnected the negative lead to the battery hoping it will reset and maybe work.  

[fishhawk]

It has to be between the plug and where the plugs harness attaches to the trucks regular wiring. the harness might be the type that attaches with a connector that goes between two of the trucks connectors or it might be spliced into the wires with scotchlocks [ a red or blue plastic connector] Possibly your ground wire came loose when turning and it pulled on the harness and damaged the connection to the trucks wiring [very easy to damage the connections with scotchlocks]. follow the plug harness up under and see how it's tied in to the trucks wiring.

[bar79lee]

sounds like fun,  i better get on it and see if i can find it.  lol.  thanks for the help,  sounds like you know whats going on.  i'll post again,  when i find out what it was......

[fishhawk]

One more question. does the truck have a seperate light that flashes in the back  that is a different one than the one that lights up with the brakes. If so it would have to have a logic box either added in for trailer lights or if the truck was built for towing it may have a logic box built in. the reason for a logic box for this potential combo of lighting is because the trailer uses the same bulb filament for both turn and brake.

[fishhawk]

The one I meant as flashing is the turn bulb on the last post, hope this makes sense the Bud light is kicking in a little.

[bar79lee]

im not sure if it has a logic box,  and if it is that, what do u think i should do?  how do i tell if i have a logic box

[fishhawk]

It will only use one if the light that flashes on the back of the truck with the turn signal on in a different section of the of the light than the one that lights up when the brake is pushed.

[bar79lee]

OK,  the blinkers and brake lights are different lights,  different sections of the entire light.  I was thinking about the part of me pulling a wire apart or damaging a connector, like we discussed earlier.  If that was the case,  more than likely it would have been the ground,  but it and the constant are the only things that work,  so maybe it is the logic box or some other component i shorted when it became un-grounded....

[fishhawk]

I work on imports for part of my $, I'll probably be by the shop tomorrow I'll look up the wiring diagrams for your truck to make sure it doesn't have some setup i've not seen before. When you can, see how the harness attaches in and post it to give me some more clues. Was the truck already wired or is this the part that Academy did? I,m hittin the sack, I'll check in tomorrow.  

[bar79lee]

no this is the way the truck was set up,  academy did the trailer the first time and it was my moms truck that it blew.  i haven't found where the wires are connected again,  it runs pretty far up there and i don't know what else to do,  i might take in tomorrow to the dealership just to get it fixed.  i'll post what the tell me and hopefully it wont be an expensive computer component