I’m wondering if there is a fuse for the water temperature gauge. I don’t see it in the fuse box. Because yesterday I discovered that there isn’t any electricity on the wire sending unit. Do you know where the fuse is for the water temp gauge?
There isn’t one per se. There will be a fused wire with voltage to the instrument cluster (your owners manual should indicate which fuse), but the temperature sensor is providing a variable "resistance to ground," which the temperature gauge in the dash is reflecting. A cold engine will have high resistance across the sensor, and a hot engine will have less resistance. The temperature sensor is specific to the temperature range, and temperature gauge in your vehicle for this reason. A certified technician from YourMechanic can inspect the electrical wiring and replace a fuse for you if you need further help.