I'm posting to this old thread rather than starting a new one. I'm getting tired of having to replace the heater control valves! I don't need heat. Is there a way to disable the valves from being in the (default) heat position so they can't override the A/C? I was thinking that the valves being in the down position would be the position that shuts off the flow of warm coolant through the system. So was wondering if I put a double spring on the valves to hold them in the down position, might that work? I have plenty of spare parts after changing out the heater control valves FOUR times already. Looking for some advice from the experts! Thanks . . .