Light fixture shorted out, replaced fixture, now no power
In my bathroom, I have 1 grounded receptacle, & (1) 2 wire light switch that controls the 4 bulb light fixture. This is on a circuit with my upstairs lights & outlets, which all work with no problem. The bathroom receptacle has never worked, I replaced it after moving in house 10 years ago, & it still didn't work. Left it alone & used a screw in adapter in place of 1 of the bulbs in the light fixture. I plugged something different into the adapter, and it shorted out, no power to the lights. The breaker did not trip. Removed the fixture and checked voltage on the black & white wires, no voltage. Check V at the 2 wire light switch, no voltage. Checked V at the 3 wire receptacle, 2 volts from ground to white, zero from black to ground, same from black to white. Have check ohms , switch & receptacle are OK. Checked feeder wires in attic with sniffer, showing voltage from junction box, although sniffer also shows shows voltage in bathroom wires,except at receptacle, which showed 2 volts on meter. I cannot see any obvious problems with wires or junction box, and cannot fully trace wires all the way without opening up plaster walls. House is 50 years old, some wiring has been replaced at some point. HELP-Guesses, anything to point me some direction? Thanks