stupid question - trailer lights

[redneck joe]

but its me and its electrical...

no trailer lights. working just fine last time i checked them on the truck but that is gone now using the car which i used to bring home from MN. only used a couple three times since and the wire stays tucked up in a storage area in the trunk.

to determine if car side just tester pointy thing to the green plug, turn on some lights and stick the other pointy thing into the other holes and look for voltage?

 

[alldodge]

In most cases if none of the lights are working with a 4 pin plug it's the ground (white wire)

https://www.etrailer.com/faq-wiring-4-way.aspx

 

[Pmt133]

I agree. It's almost always the ground.

 

[Alumarine]

This tester is good for testing the 4 wire connector on the vehicle.
This is just an example. They are widely available.

https://www.etrailer.com/Electrical-Tools/Brophy/F4CT.html

 

[tphoyt]

I have had mice chew the wires in the trailer frame several times. Always a good place to
look if tow vehicle checks out good.
And agree on the ground.

 

[Captain of the Double G's]

The most stupid question is the one not asked