EGR light on

I have a 1986 Subaru Wagon with 240,000 miles. It is a stick shift, 4 wheel drive and the EGR light just came on when it rolled over to 240,000. From past experience from a repair manual for idiots I found at the library you just unplug a connector under the dash and plug it into another. It has been almost 10 years since I have done this and I can't remember the colored plugs you exchange. This is because I am assuming the EGR valve is OK because the car runs great and the light came on automatically as the mileage rolled over. Can you help me?