I have a 2014 Hyundai Equus Signature, I would like to stop the rear window curtain from going down when i back up and when i go forward goes up i want it to stay up all the time is there a setting or a fuse to to do this.

Check the owners manual.

I agree with Mike M suggestion to check your owners manual for the issue if not call San Tan Hyundai for a service check

I am sure there is a fuse that you can take out. Check the fuse box and owners manual to locate the fuse. If you can't find anything, then maybe there is a relay or wiring harness which you could unplug to prevent this from happening

I would suggest to call the dealership or check on youtube