Hi,
I have a problem with water temperature gauge in my instrument cluster of my Toyota Hiace LH50. The car is from 1984 so I am very sure that all other Toyotas from the 1980's show the same system:
The temperature sender/sensor is mounted close to the water outlet on the engine with only ONE wire. The other wire is GROUND. The signal is a change in resistance which goes directly to the gauge in the instrument cluster. I am very sure that the gauge behaves like a multimeter-ohm/resistance meter where the gauge is energized by 12V (ignition key) and then receives the resistance signal from the sender.
Problem: The gauge is not steady and sometimes moves abruptly (very fast) up and down. The movements are only between "middle" and "low". Never "high". Now, the weird part: If the engine is running and the temp gauge shows middle=normal operating temp, I can pull the wire from the sender and the gauge does not change - it stays put. Then after maybe 30 seconds it abruptly drops to "low".
I changed the sender unit to a brand new one but that did not help. I tried to check as many connections as possible from the sender to the instrument cluster incl the ground from the engine block to the chassis but to no avail.
Does anyone have an explanation?
Lucas
I have a problem with water temperature gauge in my instrument cluster of my Toyota Hiace LH50. The car is from 1984 so I am very sure that all other Toyotas from the 1980's show the same system:
The temperature sender/sensor is mounted close to the water outlet on the engine with only ONE wire. The other wire is GROUND. The signal is a change in resistance which goes directly to the gauge in the instrument cluster. I am very sure that the gauge behaves like a multimeter-ohm/resistance meter where the gauge is energized by 12V (ignition key) and then receives the resistance signal from the sender.
Problem: The gauge is not steady and sometimes moves abruptly (very fast) up and down. The movements are only between "middle" and "low". Never "high". Now, the weird part: If the engine is running and the temp gauge shows middle=normal operating temp, I can pull the wire from the sender and the gauge does not change - it stays put. Then after maybe 30 seconds it abruptly drops to "low".
I changed the sender unit to a brand new one but that did not help. I tried to check as many connections as possible from the sender to the instrument cluster incl the ground from the engine block to the chassis but to no avail.
Does anyone have an explanation?
Lucas
