# Help! New Horse trailer tail lights don't work.



## beau159 (Oct 4, 2010)

Take it into a shop to be looked at. 

When I bought my 2003 Exiss trailer, it did not work with my husbands pickup either. The lady we bought it from claimed everything worked fine. 

We took it in and there was a problem with the ground wire on the electrical system on the trailer that needed to be fixed. Has worked perfectly since they fixed it. When we had it in, we also had them change the end on the trailer so that we wouldn't need to use an adapter for our pickup. Very inexpensive to do so, and so much easier not to need the adapter.


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## lindsayrest (Feb 23, 2013)

beau159 said:


> Take it into a shop to be looked at.
> 
> When I bought my 2003 Exiss trailer, it did not work with my husbands pickup either. The lady we bought it from claimed everything worked fine.
> 
> We took it in and there was a problem with the ground wire on the electrical system on the trailer that needed to be fixed. Has worked perfectly since they fixed it. When we had it in, we also had them change the end on the trailer so that we wouldn't need to use an adapter for our pickup. Very inexpensive to do so, and so much easier not to need the adapter.



Thanks!! We will try to bring it to a shop this weekend. It just really sucks having to pull a trailer w/o brake lights because nobody knows if we are stopping or turning 
_Posted via Mobile Device_


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## PDGx (Mar 24, 2013)

To quickly check for a ground problem, connect a battery jumper cable from your truck frame to the trailer. If lights that didn't work now do, you have it narrowed down.
_Posted via Mobile Device_


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## NorthernMama (Mar 12, 2008)

Get a test light and manually test every prong on your truck's connection. I have a "map" somewhere of different typical layouts, but quite probably it's in my glove box or in the trailer (which is now in a snow bank). Clamp on the ground, touch each prong appropriately as someone else is initiates the lights for the brake, signals, parking, hazards. Any problems at all, do the same thing, but use a part of the truck's frame, well scratched, for the ground. The plug on my truck was factory installed, but all of a sudden I started having trouble. I pulled the plug and found that they had only used 1/2 of the wire for the ground and didn't leave enough slack on top of that and I basically had a ground only when the moon was purple. 

If you SAW that the lights worked on the other person's truck and you determine that your truck is fine, the next is to check the ground on the trailer and then ensure that the trailer connector is properly wired. Sometimes people do weird things to connectors - messing up the layout.


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## PrivatePilot (Dec 7, 2009)

PDGx said:


> To quickly check for a ground problem, connect a battery jumper cable from your truck frame to the trailer. If lights that didn't work now do, you have it narrowed down.
> _Posted via Mobile Device_


Yes, try this...ground issues will create all sorts of havok. Do any OTHER lights work? Signals, clearance, etc? Does the brake controller recognize a connection to the trailer? A set of booster cables can make an excellent temporarly ground between the truck and a trailer for diagnostic purposes.

The second possibility is that that the previous owner rewired the trailer. Some people who wire their own tow vehicles have been known to do it incorrectly, and instead of fixing the tow vehicle they rewire the trailer to match their mistake. The issue with that is that when someone else with CORRECT wiring on their tow vehicle hooks up to the trailer things don't work as they should all of a sudden.


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## waresbear (Jun 18, 2011)

If you're lucky, could be your fuses.


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