If you have a poor ground connection, concurrent with a speed difference, you will have a dimming of the bulbs on that side. When you get a poor ground sufficient to change speed, you will have lower voltage. Without one side having dimmer lights not much chance of a ground problem. The way it works, think of a quick bi-metal strip that gets hot and opens then closes quickly. The greater the current drain the hotter it gets and the quicker it opens and closes. If a bulb is out on one side the current is less so that side takes longer to get hot and cycle. What was presented on the list was a perfect example of one bulb out but since that doesn't seem to be Andy's problem we're looking in the corners. If all bulbs are the same brightness they are all getting the same voltage...no ground problem and no ground intercept problem (wiring). Les