In the past few weeks, noticed that the "light bar" above the bathroom
sink is having a problem.

It's a set of three 60-watt bulbs in a somewhat standard "bathroom
fixture" outlet that I bought some 8-9 years ago and installed myself
to replace the old three 60-watt bulb fixture that my wife hated.

So, all three bulbs will dim down....and this is a pure guess....to
about 50 percent of their normal light output for ---oh 1/3 to 1/2 a
second and then pop back to full brightness.

Then, anywhere from 3-7 seconds later, they repeat. This can go on in
cycle for 20 minutes or more.

At other times, no problem...

This has been going on for a month or two....Any ideas?