This was cleared up and .delegate() was a more appropriate method:
jQuery:
// 1.1 Brands toggle
jQuery(".wpShadow").delegate( ".boxContent #brand", "click", function(e) {
e.preventDefault();
var collapse_content_selector = jQuery('#brandresults');
var toggle_switch = jQuery(this).find('img');
if (jQuery(collapse_content_selector).css('display') == 'none') {
toggle_switch.attr("src", toggle_switch.attr("src").replace("bkg-dropdown.png","bkg-dropdown-minus.png"));
} else {
toggle_switch.attr("src", toggle_switch.attr("src").replace("bkg-dropdown-minus.png", "bkg-dropdown.png"));
}
jQuery(collapse_content_selector).toggle();
});
solved .on() jQuery function not working after page updated via AJAX