The $SU(2)$ weak isospin group has three bosons, before symmetry breaking: The $W^1$, $W^2$, and $W^3$ weak isospin bosons.
The $W^1$ and $W^2$ mix to form the $W^+$ and $W^-$ bosons with electric charges $+1$ and $-1$, respectively.
So far, I can assume that the $W^3$ boson carries a neutral charge. However, I am not sure what the electric charges (which are somewhat present before the photon exists) of the $SU(2)$ triplet bosons ($W^1$, $W^2$, and $W^3$) are.
According to Wikipedia, the $SU(2)$ triplet bosons form a Weak Isospin triplet (so one boson has Weak Isospin $+1$, another one has $-1$, and the last one has 0). Also, the formula for electric charge is $Q=T_3+\frac12 Y_w$.