Yes, I am using Amazon "motorized" valves.  Purpose was to turn on hot coolant through homemade copper coils into a 5 gallon aluminum stock pot under rear seat---to heat up water for hot shower setup.  I chose the motorized valve with a Spring Return; this means you apply voltage, motor turns on, opens valve; when you shut off voltage, the Spring Return automatically closes valve.  I rigged up an old Rocker Switch (rear window defroster) into vacant bay on Instrument Cluster.  I even rigged up a BBQ thermometer into tank, and it beeps when at 122 F...I simply turn off rocker, valve closes, and after setup at campsite after a long drive I am good to go for a nice hot shower.  Works every time for the last 5 years. (I used to stop, run back to rear seat, shut off valve; electric motorized valve works way easier, makes me feel like a Rocket Scientist).

    On Saturday, May 25, 2024 at 05:23:10 AM PDT, Dennis Haynes <d23haynes57@hotmail.com> wrote:  
 
 If one want s to be really creative consider an electric solenoid valve to control coolant flow. Amazon ahs a number of 12 volt valves available at reasonable cost. This even allows for some automation. Add a thermostat switch. Consider for the rear heater. Turn off the flow to the rear heater until the return from the front is warm? Oh the options. 

Dennis