After replacing the battery and upon connecting horn is sounding?

It sounds like you have a security system that is engaged. I would do a hard system reboot; this guide will show you how:

https://www.2carpros.com/articles/step-by-step-guide-performing-a-hard-system-reboot-for-your-vehicles-electronics-systems

This guide can help as well:

https://www.2carpros.com/articles/how-to-reset-a-security-system

Please go over these guides and get back to us.

Tried those suggestions. Horn still sounds when I reconnect the battery. annoying, I pulled the horn fuse. Still no power to ignition. Any other suggestions?

Is the battery good, does it have 12 volts? Also let's check all fuses with the system on.

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

This guide can help:

https://www.2carpros.com/articles/car-battery-load-test

You may have had a voltage surge and taking out the GEM. we should do a CAN scan to confirm. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ


Here is the location of the GEM so you can check it out and replace it if a code comes up for it, you can get a preprogrammed unit by searching Google or Ebay. Check out the images (below). Please let us know what happens.

Link doesn't work.

They are working for us, can you check again?