I am installing an Orion IP67 24-12 20Amp (240w) in my ambulance. The manual has straightforward instructions, but when I turn on the switch for the 24v battery the 15amp fuse on the 24v side blows instantly. Am I missing anything? Is this just a defective unit? I've verified the battery voltage is within parameters (26.8v). I tested the resistance of all the leads and they show 0.2 ohms resistance to every other wire.
