2003 NISSAN MICRA III K12 - Testing radiator fan

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Sat 26 Oct 2019 17:33
2003 NISSAN MICRA III K12 - Testing radiator fan - MrD2018

I have been following details in the Haynes manual to test my radiator fan. As detailed in the manual, I unplugged the connector from the coolant temperature sensor and plugged a 150 ohm resistor into the connector to simulate a high coolant temperature so the radiator fan would start. The car engine however would not start! When I plugged the connector back in as normal, the engine started fine. Can anyone tell me why the engine would not start? Is there something else I need to do to make this work?

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Sat 26 Oct 2019 18:53
2003 NISSAN MICRA III K12 - Testing radiator fan - elekie&a/c doctor
Putting a resistor in the circuit has probably confused the engine ecu into thinking that the engine is in melt down mode , so will not start . All you need to do is start the engine , the disconnect the sensor . This will put the system into default mode and switch on the fan circuit .
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Sun 27 Oct 2019 14:03
2003 NISSAN MICRA III K12 - Testing radiator fan - edlithgow

If you are only testing the fan, why not jumper it directly off the battery? That's what I did recently.

Involving other elements confuses the interpretation, though you might need to test these (e.g. sensor, relay) separately.

I don't have an ecu though.

I get the impression I'm not missing much.

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