no ect/act temps

i have a 95 with a tweecer. i am not getting a signal through the tweecer for the ect or act temps. i have checked the socket at both sensors and they both read around 5 volts. i have also replaced both sensors with brand new ones, and they seem to measure the correct resitance. i hooked a dignostic up to the port and i can get a accurate tempature out of the coolant temp sensor there. i dont know whats going on? i need these sensors to work somehow. Anyone have any ideas? thanks