My guess is if you want the valve to be open all the time you can do it in 2 ways. Please let me know if I’m correct or not.
1. disconnect the cables under the car for each side. Easily done. But you need to protect the connectors with tape. Here is the risk of getting moisture in the connectors fittings, so I don’t think this would work in the long run.
2. disconnect the 2 plugs in the cars trunk instead of installing the controller. This will make the valve open all the time. No moister coming in.
for both methods the car needs to be off.