If the problem isn't the flashing unit?
 

My right turn signal started flashing at double the normal speed on my 2000 ES300. I ordered received, and installed, a new flashing unit, but the right turn signal still flashes too fast. My turn signal bulbs are not burned out. Does anybody have a thought on what the problem might be?

May sound strange, but try changing the matching left bulb. They're usually on the same circuit and if one bulb is beginning to fail, it can cause erratic blinking on the other side.

Mike

Try this file:

This is a very common problem on the ES models, and it has been discussed numerous times.

Do a search by entering "Fast blinking turn signals" in the search box.