Coolant sender

hello all have a 1300 driver

noticed temp gauge not working or is but only moving a bit
have looked on block and can't seen to see a temp sender next to thermostat housing, seems to be threaded hole but no sender also checked
Haynes and says should be blue/ yellow wire to it can't find a odd wire anywhere, any ideas

 

its probably a red/yellow wire, have a look around for a black sensor with no wire. if its missing then thats prob the issue find your red/yellow wire add sensor and job done