I am having some difficulty with the electrical on my truck. It will run great for 30-50 miles and drain the battery. Occasionally when I apply the brake it will kill the motor when the battery isn't fully charged. The previous owners decided to do a great job of hacking into the electrical throughout the truck so some works and some doesn't. The last piece of the electrical puzzle is that I have hazard lights but no turn signals, horn and probably radio if it was a stocker. Let me know what could be the cause if not I am leaning towards a new harness. I just want to drive it a little more this summer before tearing into it over the winter.
Thanks!

I'd suggest just rewire it. Centech is an awesome kit.

First thing I would do is have the alternator tested at your local parts place. Next, check for a power draw in the Bronco. Disconnect the positive battery cable from the battery and using a multimeter on amperage setting, bridge the gap between the battery's positive terminal and the positive battery cable. This should show you if there is something in the truck which is drawing power when it is not supposed to or if you have something grounded out. If you find that you have something grounding out, start pulling fuses from the fuse box, one at a time, and continuing to check for a draw. When you pull a fuse that stops the draw, you will know what circuit it is on.

I was having a similar problem with the turn signals on my 74 and i traced it back to the hazard switch. The power for the turn signals goes through the hazard switch. When the hazard switch is off, the turn signal switch gets power, and when you turn the hazards on, it kills power to the turn signal switch. Eventually, I figured out that my hazard switch was intermittently cutting off power to my turn signals (I could wiggle the switch and make it work). I ordered a new harness that included both switches from JBG for like $45.