My screened porch has a ceiling fan w/light and a 2nd light fixture, both running off an outside GFI receptacle. In short, I ran wire from the GFI receptacle to a double switch box; one switch is wired to the fan fixture, the other switch is wired to the light fixture. All has been working fine for well over a yr (passed electrical inspection, etc). Last wk I noticed neither fixture was working (may be coincidence, but it was after a lightning storm). When both switches are off, and I plug the outlet tester into the GFI receptacle it shows its fine. However, when I flip either switch on, it shows a Hot/Ground reverse. Again, this was not happening before. When I discovered the problem the GFI had not been tripped. I checked the wiring in the GFI, the switch box and both fixtures and everything is still wired ok. Any ideas? Could the GFI be bad? Thanks!

My screened porch has a ceiling fan w/light and a 2nd light fixture, both running off an outside GFI receptacle. In short, I ran wire from the GFI receptacle to a double switch box; one switch is wired to the fan fixture, the other switch is wired to the light fixture. All has been working fine for well over a yr (passed electrical inspection, etc). Last wk I noticed neither fixture was working (may be coincidence, but it was after a lightning storm). When both switches are off, and I plug the outlet tester into the GFI receptacle it shows its fine. However, when I flip either switch on, it shows a Hot/Ground reverse. Again, this was not happening before. When I discovered the problem the GFI had not been tripped. I checked the wiring in the GFI, the switch box and both fixtures and everything is still wired ok. Any ideas? Could the GFI be bad? Thanks!
...specialized tester and may give erroneous readings when using the ordinary colored light testers. If the switches are not working and you had a lightning storm it may not be coincidence...the GFI may have failed. Try resetting the GFI after first depressing the test button on the front that causes it to trip. Once spent a lot of time tracing and cutting wiring trying to find the 'issue' with a GFI only to find it was the GFI itself. When the GFI is caused to trip (button on front) make sure the function works by testing the receptacle with some device to ensure it is tripping the outlet.

Thanks for the info. I am using a GFI outlet tester so I'm ok there. I failed to be specific enough in my original question. The outside receptacle that I am running the two fixtures from, is a regular receptacle but its downwind of a GFI receptacle so its protected. However, I am able to plug in my GFI outlet tester and hit the trip button and it successfully trips the GFI outlet that it runs off of. Any other ideas?

I have never used one of those testers. Shut the power off, and remove both outlets and look at the terminals and wires. Black wire on the brass screws, and white on nickel plated ones. I think I have seen outlets where they even say black and white on them. From there, pull the cover of the breaker box and make sure the black wire goes to the breaker. You could check any other boxes the wires go through.