Fiesta 1.4 Zetec 03 Plate - Fan Issues

Honest John Back Room » Technical matters
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Thu 25 Jun 2015 18:38
Fiesta 1.4 Zetec 03 Plate - Fan Issues - Tanfies2

The fan on my Fiesta won’t turn off when it gets to the correct temperature. It comes on alright, but I have to switch it off via the ignition, otherwise it keeps running and puts strain on the alternator.

My mechanic is slightly baffled as well, he’s changed all the switches, thermostats etc, even plugged it in and controlled the fan by the ECU turning it on/off etc. It came back with no known faults.

Any ideas?

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Thu 25 Jun 2015 19:45
Fiesta 1.4 Zetec 03 Plate - Fan Issues - elekie&a/c doctor

Perhaps the fan is staying on because the engine is overheating?Does the a/con work (if fitted)?the fan will be on continuosly with a/c engaged.

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Thu 25 Jun 2015 20:17
Fiesta 1.4 Zetec 03 Plate - Fan Issues - Tanfies2
Engine is fine and doesn't overheat. Fan just doesn't switch off when it reaches the required temperature. Car has air con but it doesn't work, well it does if switched on, but doesn't hold a charge, there's a leak somewhere apparently.
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Thu 25 Jun 2015 22:48
Fiesta 1.4 Zetec 03 Plate - Fan Issues - elekie&a/c doctor

I think you need to monitor live data/actual value of coolant temperature(via scan tool) to establish if the coolant temp is actually being reduced by the fan.

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Fri 26 Jun 2015 10:01
Fiesta 1.4 Zetec 03 Plate - Fan Issues - old-school-tech

double check he has replaced the correct temp sensor, (not 100% without more details, but as far as i remember there are 2, one that controls the cooling fan via the ECU, and the other for the temp guage)

Also might be worth looking at the cooling fan relay,,if the contacts are poor inside the relay it may not be switching on/off correctly)

Edited by old-school-tech on 26/06/2015 at 10:01

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Fri 26 Jun 2015 14:09
Fiesta 1.4 Zetec 03 Plate - Fan Issues - elekie&a/c doctor

There is only one temp sensor on these,situated on the end of the cylinder head,above the gearbox.There is no dedicated cooling fan switch.It is controlled via the engine ecu.

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Fri 26 Jun 2015 16:10
Fiesta 1.4 Zetec 03 Plate - Fan Issues - old-school-tech

There is only one temp sensor on these,situated on the end of the cylinder head,above the gearbox.There is no dedicated cooling fan switch.It is controlled via the engine ecu.

Thats my theory out the window then :)

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