trailer lights out

[al cannia]

Have a trailer light problem.Took the boat out before dawn saturday and everything worked great.I pull out that evening and notice no lights working,not even clearance lights. I do have brake lights when you hit the brakes and turn signals,but nothing else,no running or clearance lights,any ideas?Have not had any light problems at all since getting the rig new last march 04,could all those bulbs have blown out,I always unpulg before backing in.Tried the plug on a another truck and no diff,still no lights,.Can the bulbs in all the clearance lights be changed?Thanks ahead of time, I know someone has some input.

 

[Craig Bennett]

Sounds like a blown fuse in the truck, and if it has a tow package it is separe. This is caused usually by a loose wire or a bare wire hitting the trailer frame, I just went through this. The fuse explains why you have turn and brake lights. Test it at the plug but save some time check the fuses.

 

[Don Wilhelm]

Al, before anything else, check the connector and make sure it is not damaged and the wires are intact. I would speculate that you have a bad ground. Most trailers are set up so that the trailer frame acts as a large part of the grounding circuit. Typically, the white wire that comes from the plug on the trailer goes back a short distance and then connects directly to the trailer. At each light you will have a short wire that is also connected to the trailer. Often times, the lights will work even though the ground is insufficient, because it will ground through the hitch ball. As the ball rusts (or the trailer), you may lose the ground. If you do not have a 12 volt test light, go buy one. Try to find one that has a sharp probe in the handle. Us the sharp probe to penetrate the insulation on the brown wire of the vehicle harness. Insert the other probe into the connector socket of the white wire. Your test light should light if the vehicle running light circuit is operable. Turn on the left turn signal and penetrate the yellow wire. The test light should flash with the turn signal. Do the same for the right turn signal/green wire. If all checks out good, connect the trailer plug to the vehicle. Do not hitch it up. Connect the test light to a sufficient ground on the truck, such as the hitch or the frame. Penetrate the insulation on the brown wire (trailer side of connector). If the light comes on, move the test light ground to a good ground on the trailer (typically a screw that is screwed into the trailer frame or a bolt that is digging into the paint enough to touch metal). If the test light comes on, then the connection is good. Take the test light to any of the running lights and connect the light ground to the trailer.. Use the sharp probe to penetrate the brown wire. If the test light comes on, the wiring and ground is good. If not, then check all of the grounds and the wire between the tongue and the light you are testing......



Man, I really complicated this response.....

 

[Jeffrey Durham]

I have the EXACT same problem right now. I will try that most complicated response from Don also. If you fing a solution al cannia, please let me know and I will do the same. I did notice that there is a grounding on the front of my trailer but something has been broken off it. hmmmm, me thinks that could be the prob!:wacko:

 

[Andre Sloan]

HOLD THE LIGHTS>>>> What type vehicle are we talking here? If this is a later model GM product, you may have a fuse problem. If you are GMC Envoy or Trailblazer type vehicle, there is another fuse box under the back seat. Lift the seat and uncover the fuse box. There is a diagram on the inside of the lid.



You are looking for a fuse that says something like TRL. On the above mentioned vehicles its kind of in the center of the fuse box, it's a red 10 amp. If it is blown, you will have stop and turn signal lights, but no tail or clearance lights.



Nevertheless, this definitely sounds like a fuse problem if it's a late model vehicle.

 

[Andre Sloan]

With regard to GM vehicles, if you want to check the connector, do as Don suggests. If you just want to check the clearance light circuit without the boat attached do this.



Turn on the vehicle lights and check voltage on the #2 hole on your 4 pin output. That is the one next to the exposed pin. Thats the running light circuit.



If you have a seven pin to 4 pin adapter (one of those round things), do as above. If no voltage, remove the adapter and check voltage on the contact that is in the 11 o'clock position. If no volts there, you have no powere to the runnung light circuit and probably a blown fuse.



But if it's a late model GM vehicle, I'd go straight for the fuse.

 

[Bill Gintzel]

Had a fuse blowing problem on my Dakota on trailer running lights. Finally found where "star" lock washer had penetrated hot lead on side marker light. Took some time and isolating which side of trailer but finally found what was blowing the fuse.

 

[Brad F]

Had the same problem when pulling with my Silverado & Trailblazer. Turned out a portion of bare wire caused me to blow a fuse in both vehicles. However, I failed to realize this until after I changed the whole taillight package!! Check the fuses!

 

[al cannia]

CRAIG,,THANKS, it was the trlr fuse blown,replaced it and everything A_OK!!I think the problem is that my Explorer Sportrac has a glass topper on it,and the dome light inside the topper is wired to the rear truck lights,when I turned on the dome it must have been too much for the fuse, first and last time I use the dome if the trailer lights are plugged in.