Cooling Temperture Sensor Pigtail..Need help

Need help on A 91' Grand Marquis W/ 5.0 Fuel Injected V8 .Does any know where this ties in to the cable harness?? Finally obtained the connecter, which comes off the sensor located in the top of the thermostat housing..but closed harness and can't remember tie in point. Would the open connection in the wiring harness make my check engine light stay on? Please help if possible. Thanks GERDIEGO