X2. With engine running around 1,500 rpm, charging system voltage should be somewhere around 13.5 volts just feeding ignition, fuel pump, water pump. If it is still low, I would start digging deeper into wiring or possible no alternator output. If it only goes low when the fans are on, your wiring is too small or your alternator output is less than fan draw. Try it old school. While the engine is running, touch a screwdriver to the back alternator bearing. If it pulls down the screwdriver, your alternator windings are live. If it doesn't, alternator isn't turning on.