But for a fan or other load that you want to PWM, a mechanical relay doesn't respond fast enough. I know the Ford Taurus had a solid state fan controller, as does my 2015 Corvette, but I'd like new parts (not junkyard harvest if I can help it!).
Naive question - on the case being drain, does that change if its PNP rather than NPN?
Summit and Amazon carry a Hella relay that is solid state but appears to fit the conventional form factor and will handle 32A per unit:
https://www.summitracing.com/parts/h...SABEgIYEvD_BwE
So I could have three of those oboard:
1) Cooling Fan A
2) Cooling Fan B
3) Fuel Pump (duty cycled down below 2000rpm for example)