Sorry but I and maybe others don’t understand what you mean by “a 10v voltage drop”. Can you explain your problem a little better.
When I disconnect the negative cable on the battery, any shorted circuits in the truck can be detected and measured by connecting a digital multimeter between the negative cable and battery ground. I am reading 10V. I did not measure amps (but should have though). A 12V bulb will show (or should show) a 12V voltage drop. A shorted circuit in something else may not show a 12V drop because of the inherent resistance and amp flow. V=IR
It’s not drawing enough current to blow a fuse because if the fuse blows it interrupts the circuit.
