Ok...so hose that is the closest to the passenger door is intake to heater core? Antifreeze flows left to right looking at the two hoses from the front of the truck. Then if valve has arrow marking flow I would splice the valve into the leftmost hose? Only real worry is if valve is not spliced right (flow against the arrow instead of with it) it may not work well. Thanks for the info...please let me know if this is right.