Arduino reads automotive low and high signals and pulling some wires to GND

i am sending negative trigger to my remote starter in my car. (mission 1).. but want to read a negative feedback..(mission 2)
issue is HIGH is 12.5 to 14.7v so i can not use voltage divider resistors to my 3.3v esp12e mcu because input is varying 12.5-14.7

how do u advice me to send zero low voltage out (so far i am doing via relays ! ) .. and how to read the low from the ecm to the mcu ? finally to to read HIGH from the 12-15v to the arduino?

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1:)pulling 12v (5mA) of the ECM of my car to ground to start the engine >>> can i just enable GPIO as output in low state? or i have to activate a rely bypassing it to resistor then ground ? or just directly to GND because it is just 5 mA /12v?

2:) reading confirmation feedback that goes from 12v to 0 momentary
3:) reading confirmation feedback that goes from 0v to 0.5v momentary > thought using ADC (pin A0) but i have 3 ffedback and only one ADC pin.

really appreciated