why passenger win dow doesn't work after regulator replacement

Hello, I’m Pete from the Car Genius team at RepairPal. I’m sorry you’re dealing with this concern on your Buick Century. Based on the information provided if the window motor worked properly before the window regulator was replaced and has stopped working since the regulator itself was replaced I recommend checking the wiring and wiring connections leading to the window motor itself to see if anything was left unplugged or was possibly damaged during the repair that was performed. It is also a good idea to have the wiring inspected leading into the door near the hinge area as it can be common on this model for that wiring to crack and break causing the loss of window operation. If the window motor was also replaced at the same time the window regulator itself was replaced it is also a good idea to have the window motor assembly tested to see if it's possibly a defective window motor that has to be replaced again. If you are unable to locate or identify the concern yourself in some cases it may be best to allow a reputable repair facility to look into the concern to pinpoint the cause. If you’d like to find a trusted, certified repair shop in your area, you can check here: https://repairpal.com/certified. If you need more advice, or have any further questions about your vehicle, we’re here to help. Just give us a call at 877-913-1554 where we will be happy to assist!