You accidentally disconnected the little black wire that connects to the crossover. it is easy to do. Simply plug it back in and it will work again
i change the thermostat and the temp switch but still not working
If your temperature gauge isn't working the problem is a bad gauge, grounded or disconnected wiring or, most likely, the temp sender isn't working.
Test gauge function with a mechanical gauge to get actual engine temp.
probably the sensor
Check your grounding on your temp sending unit.
Because they are broken is one reason
yes
The fuel gauge, temp gauge, and starter relay are on the same fuse (instrument panel). Does the car start? if the car starts then it is the module on the back of the instrument panel. it has 3 wires ( black, blue and yellow). once changed the guages would work fine.
Temp. sensor my have stopped working. Quick and fairly easy fix.
Probably the temp sending unit.
bad temp sender usually. Bad gauge rarely.
Could be temperature sensor Could be gauge