This is a small relay that plugs into a harness under the dash.

 

Thanks scr38.
The diagram shows a removal of the lower dash for access.
I'm just going to hook up to my trailer first and see if the lights/brake lights all work.
Can't do for a couple of weeks becuase I'm away.

 

Most of these should have been caught at the dealer but some might have escaped.

 

DeepCat

Even easier, throw on the flashers and check for power with a test light at the plug receptical.

 

Cool - I'll do that. Thanks kgbrr

 

Is this the relay in question?

 

I recently hooked up my hitch connector and my running lights, flashers, brakes and turn sigs all work. I'm relieved. ;>)