I was thinking about this and decided to take a look behind the switch. Looks like its a DPDT switch (201J Sigma switch). And it sends its signals to an "Raise" 12v relay and "Lower" 12v relay. Since you say the fuse blows in either direction the moment you activate the switch, I'm assuming the wiring on the switch might be crossed. So the switch assy picture could be helpful in verifying they put the spade terminals in the correct location. Since the relays have a unique connector, I'm assuming this is built up as a harness and less likely to have final assy error. So double check that switch wiring. Should be in the following order Black (Raise), Orange (Center), Grey (Lower). You can also get to the wiring to each motor (2 per side) through the pushrod covers on either side of the bunk if needed. Hope this helps.