You can check this with a couple of items, a DVOM or a 12V test light.
Connect the negative side of the test device to the frame or engine. Make it a connection that you do not have to worry about as you work ( IE; use a clamp to secure it to the ground ).
Walk the hot side of the device from the battery to all of the connections, make sure there is either 12.8V or a light on during the entire process.
Chances are you will find you blow out a wire or fuse in the system that is major. Once you find the offending wire/fuse, make the repair and continue to check out the system.
As you eliminate sections of the electrical, you can put a piece of red, green or yellow electrical tape on it and keep moving.
It may help to get someone ( wife?? ) to read the DVOM ( Digital Volt meter ) while you are jabbing the probe into parts of the electrical.
Hope this helps.
