Tail gate window not working properly

Hello,

It sounds like a fuse or relay issue. here is a guide to help you check for power with the rear window wiring diagrams so you can see how the system works and which fuses and relays to test:

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

and

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

See where you are losing power. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.