I purchased a 3-way vanity light for my bathroom and after installation one of the bulbs does not light. All sockets work. However, the last bulb that gets screwed (does not matter which one) does not light up. I replaced the unit again but ended up with same results. Any idea? Any help is greatly appreciated.

Thanks,

When you checked the wiring was it all to a common source ? If not then maybe that is where your problem is. Are all of the lights set up for simple on/off operation ?
Are the tabs inside the lights high enough to reach the bulbs ?

Are you certain you are using the correct type and wattage bulbs?