Electrical ECM Question on 99 5.0

[Cobraguy]

I am looking for a circuit in the ECM that either goes to ground or 12V (either one) AFTER the engine starts. In other words, just turning on the key will not initiate the circuit. It has to see the engine running before it switches. Does the a/c compressor circuit do this? Any other ideas? Thanks in advance guys.

 

[thorney_5]

What about the oil pressure switch for the dummy gauge? Not sure if that operates at 12 volts or if it goes through the PCM....

Edit: switch is 12 volts and controls ground side. Does not go through PCM

 

[Cobraguy]

That was a damn good idea Thorney! And you may have the solution for me. There are a lot of oil pressure switches out there that have the additional circuit like that to control the fuel pump relay. I bet I can find one. Thanks for the tip!