trouble code 0128

my 01 blazer just set this code 0128 and it says low coolant bad thermostat or bad engine coolant sensor. I checked coolant and it is fine thermostat is in normal location (right) going to replace it tonight where is the coolant temperature sensor located on 4.3 2001 blazer

Which one?
Engine or computer or air intake.
For computer sensor look around where the stat is.
It is a 2 wire sensor.
Let us know how it goes?

Replaced thermostat and check engine light went off and the gauge shows more like it is supposed to

Replaced thermostat and check engine light went off and the gauge shows more like it is supposed to

Thanks for posting back how it went.
Good Deal