Fiat Ducato radiator fans

[Manic]

If I’m not careful my radiator saga will end in suicide.
I lost all coolant from the header tank in my 2001 Fiat 2.8idtd based Hymer.
I ordered new rad from eBay , arrived damaged-returned with eventual refund, order another from Coastal Motorhomes, fitted and then it leaked-manufacturing fault, Coastal refunded stray away, then ordered a original old stock one from eBay, fitted that leaked from end cap, radiator specialist tested found leak and swapped old end cap on to new rad, lovely rad reinstalled (3rd time-at least I’m getting quicker fitting it)
Sitting in the van 2 a day later and at 8.30pm the rad fans come on, flat out, disconnected the rad switch to stop them , cleaned plug with contact cleaner but as soon as I plug switch back in the fans start.
Any suggestions, please

 

[Figaro]

Is there a thermostat somewhere that switches it ?
Presumably it's sticking or gone faulty, no idea where it would be though

 

[chain driven]

If I’m not careful my radiator saga will end in suicide.
I lost all coolant from the header tank in my 2001 Fiat 2.8idtd based Hymer.
I ordered new rad from eBay , arrived damaged-returned with eventual refund, order another from Coastal Motorhomes, fitted and then it leaked-manufacturing fault, Coastal refunded stray away, then ordered a original old stock one from eBay, fitted that leaked from end cap, radiator specialist tested found leak and swapped old end cap on to new rad, lovely rad reinstalled (3rd time-at least I’m getting quicker fitting it)
Sitting in the van 2 a day later and at 8.30pm the rad fans come on, flat out, disconnected the rad switch to stop them , cleaned plug with contact cleaner but as soon as I plug switch back in the fans start.
Any suggestions, please

Hi you say both fans are running. That would indicate that the control box ( located on the fans housing) is faulty they are prone to water ingress due to there position .hope this helps

 

[Manic]

Is there a thermostat somewhere that switches it ?
Presumably it's sticking or gone faulty, no idea where it would be though

There’s a switch in the bottom of the rad, but I would like to check before buying a new one and draining coolant again.

 

[Landy Andy]

I would think the switch would operate a relay as the power required for the fans will be high. I’d suggest you check your relays.

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[philann]

Is one of the fans for the air con? They seem to run almost continuously!

 

[Bessy765]

The smaller one should come of first the if the temp continues to rise the second (larger one) follows. If the air con is turned on the larger one will run the sensor in the rad will have three wires a supply and the two returns one for each fan make sure during fitting this has not been damages where the wires go into the sensor, if moisture is the it will link all three wires and both fans will run.

 

[Manic]

No air con on, both fans start as soon as I reconnect it, I’ve sprayed it with contact cleaner to dry it out with no effect

 

[chain driven]

From what you say I’d say control unit u/s . Find temp. Signal supply ,disconnect if fault still there then unit has shorted

 

[Manic]

More testing today, on a cold radiator.
3 wires to the switch and if I put my multimeter on continuity, I get a reading on common and one wire but not when I test common to the other wire.
Put a jump wire from common and one wire both fans start, so it’s the switch I think

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[the1andonly]

Suicide is painless, so MASH says.