All really good advice so far. But, even if it was a fuse, why would BOTH brake lights go out at the same time? About 99.99999% of the trailer connectors on 99.99999% of the motorhomes/trucks/space ships etc. have:
1. Right turn/brake
2. Left turn/brake
3. Tail/marker
4. Ground
.... And so on. I can see one side (brake light AND turn signal since they're the same signal at the trailer connector) but, both at the same exact time? I'm by far, not the sharpest tool in the shed so, I could be really blind as to what you're suggesting. I do know about the pin thing where, those pins collapse a bit and, one needs to get into them and pry them apart just a scoch so they make a better contact with the female counterparts inside the other half of the connector. I had a problem just like that in setting up a buddies Jeep for towing. Took a bit of head scratching on that one.
Anyway, it will be interesting to see what the OP finds out is the problem.
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND