Like the title says, What exactly does it do. I know its ground controlled by a 1psi hobbs pressure switch, and gets 12vdc control power from a splice to purge control solenoid. I know it manipulates the IAT signal wire, but how? what does it exactly do to the signal for IAT?

 

Thanks for the help everyone! Found out its a resistor. when under boost. More thank likely a 15k ohm resistor that tricks the ECU into thinking the Intake air temp is -4 degrees F. forcing enrichment