Headlights are not working?

No relay. Power from the battery goes to the switch, from the switch to the dimmer switch and out to the high and low filaments in the lights. If you lost all headlights high and low it's more likely either the power isn't getting to the light switch or a bad ground at the other end.
To check, go to the left headlight and pull the connector. Hold it so the connections look like a U and the left terminal is the ground, bottom terminal and right terminals are headlights. Turn on the switch and use a simple test light connected to battery positive, lights on low beam you should have power to one terminal, high to another. No power at any = there is a problem between the dimmer switch and the battery. If you have power, the ground has failed. That is the black wire that goes to the core support on the left side. Use the test light connected to battery positive, does it light when you touch the left terminal in the light socket? If you find no power at the socket, you need to start tracking back through the circuit. Go to the headlamp switch, with it off do you have power at terminal B1? No- bad power feed from the battery to the switch.

Okay, so all the other lights work just the headlights are out? It's possible they are blown but not likely, there are a total of 4 filaments that would have to fail if you have no high or low beam. B1 should be a battery feed so Red or Red with orange for lighting. A simple cheap test light would make it easy to test all of it.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Okay, then you need to check for that power at the input to the dimmer switch or go and test at the headlight connector itself for power the driver's side headlight will have 5 wires for the three connections, the single black is ground, the other two pairs are high and low beam. Turn on the lights on the high beam and check all three terminals. One should have power. Now switch to low beam and you should have power on the other terminal with 2 wires. If those work, then the power is getting from the switch out to the connector. From there as all 4 do not work I would find the black wire and follow it from the bulb socket to the bolt on the side of the radiator support, it's very likely rusted and bad.

Okay, if you have two that have power, test the ground, if you connect the test light to battery positive and touch it to the ground contact in the socket does it light? If yes then replace the lamps, it is extremely rare for them to fail that way, each one has what amounts to 2 bulbs inside each lamp, so for all 4 of those to fail it should have been very noticeable as you should have seen something like left side high is out, then right side low then right side high and then no lights. But if all of them were working, then they don't all at once it usually isn't that the bulbs have failed.

You are welcome. I prefer electrical on many vehicles, at least until you get into the 2000's and up. Then it can get fun when you have 4 different modules all involved in turning on the headlights. Glad to hear the lights work.

You are welcome. I like to work through this site as I can post information easier. NC, watch out for the snakes.