Hi All
I have a problem with the cooling fan not switching on. The fan works fine if I remove the wires from the green thermo. switch on the rad. and join the wires. I bought a new thermo. switch and this did not work. The Fiat dealer got me another but still does not work. I believe the switch should just create an earth across the contacts when hot so tried putting in it boiling water but this did not create an earth but not sure if this is a valid test?
Can anyone suggest what the problem can be. The fuse and fan are fine as they work if I bypass the thermo switch on the radiator.

Hello, join the Club (not this one! the club of Siecent/Cinq Colling Issues)
I have just had a Nightmare with a similar Issue...
I will go get the link and come back bud

Hello, what year and size engine is your Car ?

Sounds promising. I saw there had been a couple of earlier posts but the problems appeared to be a bit different

Sorry should have said - it's a V reg. Sporting

Here is the Link
https://www.fiatforum.com/cinquecento-seicento/204808-sad-hours-work-fan-n-pas-issue.html
I am unfamiliar with other varieties of Siecento's
WHAT SIZE ENGINE

If you don't think it's the thermo switch, are you sure the thermostat is functioning correctly?
If it is stuck closed, hot water will not go to the radiator and so your thermo switch won't ever get hot.
Also check for blockages in the radiator top and bottom hoses to see if water flow is being blocked.

Re: Seicento Sporting cooling fan not cutting in

The info in the link sounds pretty complicated, was it the relay in the end?
The engine does not get hot until it's stands which I would expect with the fan not working, so I thing the thermostat is working. I assumed the green thermo. switch just creates an earth when hot which would be the equivalent of joining the wires that plug onto it. This is why I tested by joining the wires and the fan comes on fine. Does the switch have to get much hotter than boiling water as per my test?

Does sound like a dodgy switch, or in your case three of them.

I presume you have bled the car each time you changed the switch out.

Cheers

SPD

Intermittent earth making contact only when you apply tension to the wiring loom?

Just come back and seen the posts. To be honest I have not bled the system after filling! However when I take the thermo swith out the radiator the coolant has poured out through there so the the radiator would have been full.
Could air in the system stop the thermo swith from functioning?

Hi All
I have refilled the rad. with the bleed screw open this time to clear trapped air. Run the engine until hot but the fan did not cut in. One other thing that may be relevant is the warning light is not comming on now when hot. Does not come on with the ignition either so light may have blown? All the problems started when the original fan packed up and blew the 30 amp fuse so may have blown the warning light. This is frustration, may be easier just to put a maual switch on the fan.

You're likely to forget to switch the switch on sooner or later..........

Pretty sure it's wiring related, but as for testing, with a multimeter on the ohm setting you should see continuity between the contacts at something like 95 degrees C.

Note that there are two bleed screws, one near the windsreen reservoir, one on the bulkhead where the hoses pass through to the heater.

fingers99 said:

You're likely to forget to switch the switch on sooner or later..........

Pretty sure it's wiring related, but as for testing, with a multimeter on the ohm setting you should see continuity between the contacts at something like 95 degrees C.

Note that there are two bleed screws, one near the windsreen reservoir, one on the bulkhead where the hoses pass through to the heater.

Click to expand...

Hi Fingers - I noticed there were 2 bleed screws although coolant only came out of the resevoir one

I've got the same problem. I've replaced the 30 amp fuse, the rad fan, and the temp switch. The fan works when tested through the temp switch plug and all the pipes and rad are hot suggesting the thermostat is working. I'm at a loss:bang:. My coolant just keeps boiling over and the fan wont cut in.

Please help!!!

hi you say the coolant dont come out of the bleed screw near the heater. dosent always. i noticed that if you dont blled properly then the fan dont come on for a long time, when bled right it should kick in at about 90. run the car and then unscrew the heater bleed screw and the water should come out like a fountain, check the other bleed screw after and then you should have the fan coming on at about 90-95. the air pocket in the system can make the sensors faulty, so make sure its bleed right. can cause many problems in not. good luck!!!!

Good idea to cold bleed with the heater on full first..........

We seem to have an identical problem. Everything points to the thermo switch not working but I have tried 2 new ones. The only other thing I have noticed is the temp. warning light is not working now although I am not aware of any direct link

Warning light will not work if there's a lot of air in the system..............

I have tried the heater bleed screw with the heater on and liquid does come out. Most posts seem to be pointing to air in the system but I am not sure what else I can do.
I mentioned that the temp warning does not come on now, it does not light up when the ignition switch is initailly turned on either but presume it should?