I have a GFI plug in my downstairs bathroom that controls three plugs upstairs: guest bathroom, and two in my master bathroom. My wife tripped the plug in the master bathroom with her hair dryer. I went to reset the GFI plug in the downstairs bathroom, but it was not tripped. My wife was still able to use her hair dryer on this plug (downstairs bathroom). The three plugs upstairs do not work. Using my caveman voltage tester, I get the little red light to turn on, but I am not able to use the plugs for even low voltage items (i.e. 20 volt lightbulbs). There are no other GFI plugs controlling these plugs. I've tried switching out all the plugs in the bathrooms upstairs. They still don't work. 3 bad plugs + no hair dryer in our master bedroom = 1 unhappy wife.

Any ideas?

Thank you for any help you can give.

The GFI may be defective, you could remove, connect line to load(bypassing GFI), and see if power upstairs. If you do Replace GFI. Take note of line and load for reassembly.