HELP----AC fan blows when thermostat is set to OFF

I can run my fan without AC too but the problem is I can only shut the AC fan OFF by flipping the breaker or unplugging the trailer from power. I have the thermostat set to OFF and the AC fan still runs. That should not be happening. I'm trying to find out why. Here is a pic of the new wiring install. The shop is telling me it has nothing to do with their install but I don't believe it.