I had three light fixtures stop working at the same time. #1. Laundry room ceiling fixture #2 Outdoor porch light (outside of laundry room exterior door) #3. Ceiling fan and it's 4 lights ( in living room located next to laundry room) The ceiling fan lights are controlled by a sliding type dimmer switch and there's a separate simple on-off switch for the ceiling fan.. I removed #1 and #2 fixtures. Using a Wiggins type voltage checker, I checked between hot leg and neutral leg at both mounting boxes and got no readings. (Yes, breaker and both light switches were turned on). Then I checked between hot leg and ground wire at both boxes and there was 110-115 volts, which was expected. Then I checked between neutral leg and ground wire at both boxes and was surprised when Wiggins showed voltage readings at both boxes. Not having a "Volt Meter", I don't know exactly how much voltage, but I could tell it was weaker than 110-115 volts by the Wiggins minimal spring jump and indicator light being less bright. I removed the ceiling fan light's dimmer switch from the wall box but left the wires connected. I slid the handle down to OFF position and rechecked the neutral to ground readings at #1 and #2 boxes. There was no longer any voltage, so... I went back and slid the dimmer handle up, to the on position, then checked #1 and #2 again. Now the weak voltage was there again. I replaced the dimmer switch with a new one and did the two voltage tests again. No difference, got the same readings as with the old dimmer switch. I do not understand how or why I'm reading voltage on the neutral legs to ground. Never seen it before. Any help out there would be most appreciated. Thank You!

I'm not sure I follow all the test you did. I'm sure you know this but I think perhaps it should be said anyway. You are aware that a white conductor in some switch loops can be a hot rather than a neutral.

If you are getting voltage between a true neutral and the ground, that indicates a break or bad connection in the neutral conductor. That break or bad connection can further down the line on the way back to the breaker panel, and includes the connection to the neutral buss bar in the panel

Kind of sounds like that is what this is..

What changed? What caused them to suddenly go out? It sounds like somewhere possibly on another circuit the polarity is crossed, or the neutral is being used as a ground. Did you get a new lamp, or new appliance, or radio... if you did, unplug it and see if that fixes the problem.