Dash light and passenger taillight out at same time

Hi,

If you lost power to both and the taillights are still not working, I suspect the switch itself has failed or it could be a fuse.

Take a look at pic 1. Check the two fuses I circled and let me know what you find. Here are a few links you may find helpful:

https://www.2carpros.com/articles/how-a-car-fuse-works

https://www.2carpros.com/articles/how-to-check-a-car-fuse

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

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Let me know if you have questions.

Joe