trailer brake light not working with car lights on

[gardenstatesurfer]

guys,<br /><br />i just purchased a new tail light assembly for my boat trailer.<br /><br />everything (blinker, brakelight) works fine with the truck lights turned off.<br /><br />however, when i turn the truck lights on and hit the brakes, the brake light turns off (rather then becoming brighter). blinker still works ok.<br /><br />if anybody can help i would appreciate it. my trailer has a brown wire and a yellow wire.<br /><br />as you can tell, im new to this electrical stuff and am wondering if perhaps i bought the wrong type of taillight assembly.<br /><br />thanks all,<br /><br />dave

 

[cp]

Re: trailer brake light not working with car lights on

Suggest you verify that the white wire from the trailer connector is making good contact to the trailer. Good luck.

 

[rg33]

Re: trailer brake light not working with car lights on

Also, check that the wire colors are matching.

 

[gardenstatesurfer]

Re: trailer brake light not working with car lights on

is the white a ground? i only saw a brown and a yellow wire....

 

[Silvertip]

Re: trailer brake light not working with car lights on

The brown wire on the light is the tail (running) light. The Yellow wire is the turn signal. If the light does not have a white ground wire, one of the bolts that secures the assembly to the trailer must function as the ground. If neither brake light works, the trailer ground is probably bad. That's the white wire in the trailer plug. That wire must be firmly gounded at the trailer. Likewise, the corresponding wire on the tow vehicle must also be firmly grounded.

 

[Pony]

Re: trailer brake light not working with car lights on

i like to put a little vaseline or petroleum jelly on the lights(on the grounding bolt) and wires where they ground to the trailer to make the connection better....also a good idea to brush the trailer with a wire brush in those spots.

 

[tommays]

Re: trailer brake light not working with car lights on

<br /><br /><br />the ground is inportant and the most common problem when its bad you can all kinds of strange feed back <br /><br />tommays

 

[gardenstatesurfer]

Re: trailer brake light not working with car lights on

thanks guys i will check that.

 

[levittownnick]

Re: trailer brake light not working with car lights on

To test for a poor ground, turn on the lights and observe the trailer lights while connecting a temporary ground between the tow vehicle and the trailer (A jumper cable is great for this test.). If there is a jump in the brightness of the trailer lights, then the ground needs fixin.<br /><br />(If one set of lights go off when annother is turned it is a sure thing that a poor ground is at fault. That is because the filaments on the stop/tail lights use a common connection for grounding and if this ground connection is missing, the filaments are in series. Then when voltage is applied to the previously unlit filament, both ends have the same voltage therefore there is no voltage across the filament. (both sides of the filament are connected to the same poin).