Sam asked: On high-beam, do both the low-beam and high-beam filaments light simultaneously? Not sure about your cars over there Sam, but my Holden (Aus) lights only the low beam or high beam. The only time you can get both on is momentarily when using the "pass" or "flash" switch, the contacts for a short time make-before-brake. HTH, Danny wallad at devetwa.edu.au