Using electrochemical scanning tunnelling microscopy, we measured the potential-dependent kink energy and the corresponding dipole moments of kinks at step edges on vicinal Au(001) surfaces in chloride and bromide containing electrolytes. Combining the results of the potential dependence of the kink energy with impedance spectroscopy data for the surface charge, we can directly deduce the dipole moment of kinks at the Au steps with co-adsorbed Cl⁻ and Br⁻, respectively. We find μ^Cl = (6.0 ± 0.7) × 10⁻³ eÅ and μ^Br = (10.1 ± 0.6) × 10⁻³ eÅ.