Ecu is awake as long as the ECM relay is turned on(controled by pin 21)
What car it is? On what pin is aux pump relay?
2008 R32.ME7.1.1 ST10 Aux pump relay controlled by ECU pin 48.
The ECU needs power at pins 3,21,62 .
Pin 3 and 21 go through relays to get power. Only the pin 3 relay is controlled by the ECU (by Pin23). Pin 21 relay is controlled by the "Multifunction control module relay #2"
Pin 62 is either permanently on or through the ignition switch.
How does the ECU determine that the after-run has finished and shuts down the relay you mention?
just use a lower after run temp thermostat. much easier. circa 2001 mod.
Unfortunately the R32 doesn't seem to have one of these, just a standard thermostat.