symptoms
1. garage lights won't turn on
2. garage door opener won't go up/down
3. when light switch is off, garage opener sensors light up
4. when light switch is on (lights don't go on), sensors go off
5. Voltage tester shows 104 volts in all outlets in garage


what should I do (besides calling an electrician)?

the problem began soon after the first rains in 6 weeks

the power to the garage is underground conduit from the house, under
the yard to the garage.