'88 90q temp sensor?

[Steve Meyer]

My temp light is flashing, so I'm trying to trouble shoot...the temp gauge never goes above 1/4 of the gauge and I have no overheating issues...heat works good too. I'm thinking it's the switch/sensor at the bottom of the radiator. I haven't replaced one of these in a while? I think it's the multi-function temp sensor. What's the actual name and where can I get one?  Is it the fan ambient temp switch? 

Thanks!
Steve