The plugs on the axle have four terminals. In the factory Power Wagon configuration, two are for locker activation and require 12 volts. The other two are for the computer to sense positive locker activation and require 5 volts. Once the computer senses activation, it will turn on the dash indicator light. Since our ’94 doesn’t have any such bells and whistles, we will look for locker activation the old-fashioned way, by watching for tire slippage. Since we didn’t care if we fried the sensor, Wade tested all the terminals until we could hear the locker engage. Since the magnet on the locker doesn’t care which way power is flowing, we just had to find the correct terminals.