Trailer lights problem

[mike71]

I am having some problems with my trailer lights. The right tail-light and left, right, and bottom marker lights do not work. All of the other lights work just fine. The first thing I did to test was to get new bulbs for those lights. So that eliminates the bulbs being bad. What else can I do to troubleshoot this problem? <br /><br />I have one other questions. When I turn on the turn signals, the break-lights do not come on. Is this normal or is this another wiring problem?

 

[vranasaurus]

Re: Trailer lights problem

Check to make sure that the trailer is properly grounded.<br /><br />Without a proper ground the trailer lights will do some goofy things.<br /><br />If it is a 4 pin connector the white wire should be grounded to the trailer.<br /><br />Hope this helps.

 

[QC]

Re: Trailer lights problem

A test light would hep you a lot. Agree on the ground. <br /><br />As to your other question, if you turn on the turn signals, the opposite brake light should still work. Since trailers typically use the same light for both brake light and turn signal it can't flash and be on at the same time, so basically the opposite light becomes the only brake light while using the turn signal.

 

[Silvertip]

Re: Trailer lights problem

Check the individual grounds at each of the lights that don't work. There may be a separate wire, or the screw or bolt securing the light to the trailer makes the ground connection. Make sure those connection points are clean and tight.

 

[QC]

Re: Trailer lights problem

Agree with UIS. I have one flaky running light that needs a little encouragment once in while. Just a wiggle on its own ground makes it go every time.

 

[phatmanmike]

Re: Trailer lights problem

this is why i use LED's

 

[jtexas]

Re: Trailer lights problem

Originally posted by myoutboards:<br /> this is why i use LED's

??? <br /><br />LED's require a complete circuit to light up, don't they?

 

[chuckz]

Re: Trailer lights problem

Yes, but since they require so much less current they can tolerate a higher resistance in the ground before they don't operate. For instance an LED requiring 10ma (0.01amps) with 100 ohms to ground will see a 1 volt drop (.01 X 100). A conventional lamp drawing 1 amp, with the same 100 ohms to ground, will see a 100 volt drop (1 X 100). Obviously, long before you get to 100 ohms the conventional light will not work.

 

[fondafj]

Re: Trailer lights problem

LED's require a wired ground and do not work well grounded to a trailer frame. In order to function correctly all connections, including the ground, need to be high quality and low resistance. The problem described sounds like a poor trailer to vehicle ground or none at all. Converting to LED's without fixing this problem 1st will be a frustrating troubleshooting adventure.