Maybe swap the red for white and see if that makes a difference. Sometimes wire colours don't make sense and the white might just be the 'hot' wire.
In fact, the more I think about it these are Humbuckers and both are probably hot wires for each coil and therefore if not coil splitting maybe try soldering both on the same lug? Most 4 wire guitar HB's have red & white soldered together to complete the circuit and separated if doing coil splits.