What causes a temperature gauge to not work and then once in awhile work for a short period of time?
- Failing temperature sending unit
- Bad connections or wiring problem
- Faulty gauge in dash
Coolant Temperature Indication System, Engine
The engine coolant temperature indication system is a magnetic-type indication system consisting of:
•the water temperature indicator sender unit located in the engine block or cylinder head
•an engine coolant temperature gauge in the instrument cluster
The water temperature indicator sender unit operates as follows:
•changes resistance according to engine coolant temperature, which varies the current flow through the engine coolant temperature gauge
•the pointer position varies proportionally to the current flow.
•resistance is high when the engine coolant temperature is low, and low when the engine coolant temperature is high
•the pointer of the magnetic engine coolant temperature gauge remains in position when ignition switch is turned to the OFF position
•pointer will move to the correct indication whenever the ignition switch is turned back to RUN position
•pointer may indicate at the top of the normal band with the engine coolant temperature within specification, under certain driving conditions such as heavy traffic or stop-and-go driving in hot weather
Engine Coolant Temperature Gauge
The engine coolant temperature gauge is identified by a thermometer symbol:
•H means high temperature
•C means low temperature
•the solid band between C and H is the normal temperature range
Water Temperature Indicator Sender Unit
The water temperature indicator sender unit:
•is mounted into the thermostat housing bypass tube. The signal sent to the engine coolant temperature gauge varies with the resistance of water temperature indicator sender unit, which depends on the engine coolant temperature.