I have owned this truck for a couple months now and I have always wondered what this is. It is definitely not factory. I tried to look where the wires go but they disappear into the nest under the dash. Any help would be appreciated.

 

No, not factory
I wouldn't think trailer brakes, they are usually 4 wire

What do you need that's portable, something you would unplug frequently, to take inside for theft reasons, or to switch to another vehicle, or ??
Only reason to have a plug-in that is easy to get to is because you need to unplug it, lol
GPS/MAP unit maybe, but just need 2 wires for that?
OBD1 adapter port?

 

I think you are right. I looked again where the wires went and it goes straight up towards the pcm. The only thing that doesn't make sense is that there is nothing in the engine bay that connects to the obd1

 

Then that's not what its for