System using transistors 5v input running 30amp fan

Discussion in 'General Electronics Chat' started by J11ames0208, Jul 9, 2016.

  1. J11ames0208

    Thread Starter New Member

    Jul 9, 2016
    Hi there I am trying to figure out the electronics behind a get me out of poop situation. My car won't turn the cooling fans on, but I know from testing that the ECU sends a 5v reference to the engine temp sensor, and then when at temp it sends volts to the mini heater in thermostat to melt wax and force early opening of it. I want to use the signal return wire back to the ECU in the thermostat wire to power the fans in some way. Spent all yesterday thinking relays would be the way, only I have just learnt that relays in general on 12v dc require 12v both sides. I'd thought maybe 5v would still work in part. Anyway now im learning about transistors, only I think they only work for low load applications. I need to remember that I have to be cautious of amp draw so as not to fry the ECU.

    Is there some direction of learning that someone can point me down, to come up with a safe way to have the 5v ECU signal wire turn on the radiator fan. I'm think the signal wire is a constant five volts due to its purpose. Heating up wax in the thermostat to be able to open the thing early.

    Relatively new to electronics and so far deeply addicted.
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    So, if the thermostat heater is off you want the fan off, while if the heater is on you want the fan on - is that right?