Oldsmobile/Buick Repair: Cooling Fans, buick roadmaster, temp sensor

Question
I  have a 1994 350 Buick Roadmaster I am having Problems with the primary fan.I replaced the temp. sensor and the fan will not run until i unplug the temp sensor this is when the temp has reach a high temp. then both fans kick on I notice that the wires coming from the plug has been pigtailed when the car was in the shop before is there something else I am overlooking

Answer
hi micah.well bye unplugging the sensor and the fans operateing,you are essencially checking the fan circuit so a prob with the fan harness would not be a concidderation.but most likely the temp sensor is the wrong one or the dash guage is not accurate.or possibly a bad fan relay.good luck please rate my help ty billymac