Right side no taillight/front marker light not working

Welcome to 2CarPros.

There are a couple things we need to check. First, since it worked when the new switch was installed, my first suspect is there is a bad connection at the switch. What I want you to do is remove the switch and confirm the pins in the plug are not corroded, pushed in, or damaged in any way.

Next, I attached two pics. I circled the tail light relay as well as the fuse and splices that tie the front and rear light together. Check those things as well.

Here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here are a few links you may find helpful:

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 the brake light or turn signal is working as well.

Take care,
Joe

I've checked everything in the test that you said and everything checks out okay. I did notice the right fog light bulb is busted. If the fog lights were on driving down the road and the air was blowing the socket around could it short out somewhere and cause the right front marker light and right tail light to go out and blow a fuse?

Welcome back:

Yes, something may have shorted, Have you checked fuses? Also, have you checked the connection at the switch to make sure nothing is loose or if one of the pins on the connector is corroded or pushed in and not making a good connection?

Let me know.

Joe