You have a few questions here , so let me take them one at a time.

High fan prob has bad fuse b/c of excess draw due to binding fan motor The fuse is on top of the relay I posted for you. It is 30A..The relay is behind fuse box, in relay compartment [ 6 screws.] This high fan is activated by unplugging the blu sensor as you noted .. This is a coolant temp fan circuit and has nothing to do w/ac fan

OK..ac/low fan
This fan is activated by the pressure sw at the drier..BUT, before condemning the sw, one wants to verify the LOW FAN circuit..this is done by jumping the sw ..just slide back the white covers on the sw pigtail wires and jumper w/screwdriver [ leave the sw hooked up, just jumper the connectors]
DO NOT confuse this sw with the other spade connector sw at drier.
If the low fan comes ON , you know that the circuit is fine , except the pressure sw is not activating..BUT, it is most commonly not the sw, but rather low freon level that is the problem..if the level is slightly low, you can have cooling, but no fan b/c the high side pressures do not get to sw cut-in spec. The design is for this low fan only to come on when a High Termal Load condition exist.
He claims to have checked that and he probably has, but I would do the jumper test just for self satisfaction. I hardly ever see bad high side pressure fan sw, but tons of no fan due to low refrig levels.
The trick is to check the circuit w/jumper before any other steps are taken.