Originally Posted by JimBlake
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The fan switch is in thermostat housing, it has a plug with 2 wires. Just an on/off switch, it's not really a 'sensor'. Unplug it, jumper the wires together, turn on the key; that should make the fans run.
The engine coolant temperature (ECT) sensor is at the upper hose nozzle, it's also got a plug with 2 wires. That's for the fuel injection ECU to measure temperature.
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Ok, before I replace the sensor / switch I jumpered the thermostat housing switch and with the key on, both fans came on. Then I jumpered the top hose water outlet switch and only the radiator fan came, this with the key OFF.
Question: if after replacing the switches the problem remains the same, would there be harm in jumpering the fans so they both come on every time the key is on?