Yes high beams work, all lights were working before the replacement, but I forgot to mention that this is the second alternator. What happened is I bought the first one it caused an overcharging situation, I checked the amps and it was putting out 18.65 amps at the battery while running so I shut my truck down. Called my mechanic and we both agreed that the regulator was bad. Took the alternator back to Napa got another installed it and all was good so I thought. I have the auto light option or what ever it is called when it get dark enough the exterior lights come on all the other lights work just not the low beams.