Ergh...

Note - look at wiring before pulling out, take photo - then pull wires out it's much easier that way.

Ok, look I just don't have the time right now to do this one, I can help you, I just need to pull my flashforge open, trace the wiring and tell you which one goes where, but man that's time I just haven't got right now sorry.

If you have a multimeter, just make sure the output is 24 volts before you swap them over, as one of them is the thermistor, so don't swap unless you check.

I would personally be doing a preheat and see if the hotbed temp reads OK and so does the nozzle - a fan not running will not kill it, trust me. Once you have confirmed that the heating is working, the left extruder heats when you want it to and the right does etc, and the hotbed works... then check the voltages on the fan outputs on the board, and as I said swap the two that have a 24v output.