Thermoquad Problem

When I bought my 73 dart it had a carter AVS on it. well it finally craped out and my dad found a reman thermoquad for cheap. well it came in the mail last night and it had a wire comming off of it and i didnt know what it was. well found out it a idle air enrichment soliniod. 1st question is what all does that do. 2nd question will it be a good idea to hook it up and 3rd how would i go about hooking it up. is it a constent 12v? key on? hook it to a switch? etc