Regarding the 3 relays behind the driver-side headlight. Based on Barrera's experience and comments, I would replace all of them to rule them out as a possible cause. Those relays are very affordable. The original ones might have gone bad from age, wear and tear, electrical over-load, dampness, water infiltration, or a combination of reasons. Being adjacent to the main battery, battery acid boil-over might have got on them creating a problem.
When the 3 relays are out, look for corrosion on their terminals and the sockets they plugged into. If you see any corrosion (white or green colored crusties) I advise to soak each socket in a CLR type of product (using a small jar full) to dissolve the corrosion, then rinse them well in clean water and dry them well. Once perfectly dry, inject silicone grease into the sockets, then connect them to new relays.
I once bought a non-running 1991 Mercury Capri XR2 off a flat bed tow truck. That vehicle had open connectors, not sealed with gaskets like most cars have. I soaked every under-hood connector in CLR, dried everything well with compressed air followed by a hair dryer, injected silicone grease, and reconnected. The car then ran perfectly.
If you don't have compressed air, try the exhaust of a vacuum cleaner.