Mercury Repair Questions? Ask a Mechanic for Answers ASAP
This problem is caused by a weak circuit breaker in the headlight switch. The headlight circuit is protected by a circuit breaker, not a fuse. If the circuit breaker gets weak then the lights will cycle off then back on. The circuit breaker is built into the headlight switch so replacing the switch is the necessary repair for this problem.
Park lights and dash lights are on a separate circuit. If you lose all lighting then your problem will more likely be a loose main power feed at the battery, starter, or underhood fuse panel connections.