Mercury Repair Questions? Ask a Mechanic for Answers ASAP
You will need to test fuse no.16(15amp) in the under hood fuse panel if this is good the next step would be to check for 12V at the headlight switch on the tan/white wire.
Here is the wiring schematic to help you
If you have it there then check the brown wire on pin 12 with headlights on.
You keep referring to headlights, this will fix no tail lights?