Help! No trailer lights work

You're welcome. Kind of helps that I drive a 2012 Cascadia, too, LOL!

 

Without ground... 1 million volts won't spark an 1157.

Also, if you've ever sprayed a water hose in you're cab floor to rinse out the vinyl flooring, you easily could have corrosion in that panel or somewhere in that firewall.

 

Good. Always check ground FIRST w electrical issues.

Glad u got it.

 

TA mechanic? That doesn't sound encouraging. The electric cord has 2 ends, you know that, have you spread the pins with a small screwdriver or knife? Also, the wires are bolted into the plug with screw tensioners, you can check those. If you're getting intermittent functionality, it sounds like a fairly straightforward (inexpensive and easy to repair) problem. Best.

 

There is a fuse box under your hood / driver side / near the fire wall. Check trailer lights fuse.

 

What ended up being the problem? We have 2 2013 Cascadia day cabs with the same problem

 

....did you not read the thread?