1993 Toyota Camry

More than likely this is an issue with the switch.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-a-headlight-switch-works

However, the way to test this is to check the voltage coming out of the switch. Here is a guide that will help with this type of testing:

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

Below you will find the wiring diagram that will help with the testing so you will need to make sure there is voltage coming from the switch when it is on, if not then it is confirmed that the switch is failed.

The process from the manual is below as well. Please let us know if you have other questions.

Thanks