(T) Beep Beep - water in fuel filter

Just had 84k service last friday and took car out today for a run. 6-7times got warning message, "water in fuel filter". over a approx 80 miles period.

I definately paid for the new filter and it certainly looks like a new one. i've called dealer and they think maybe switch has gone.
i should add that the car was displaying this message before the service too buy assumed was genuine and left it as service soon. seems to come up when going up or down hill but not everytime

dealer charging - switch £15 plus vat plus 0.25 labour, total about £35

Anyone heard of anything similar and also how hard to change these switches? would it be the one on the bottom or the one at the top on a black plastic collar type thing?

cheers

update;
well checked elearn which shows it's the switch on the bottom of fuel filter.

Removed the filter and cleaned up the switch with WD40. Also drained the filter a bit in case there was water inside.

After 40 mile drive no BEEPS, hooray, hope it's fixed

The WIF sensor is simply a switch which sits in the fuel / water separator and activates when the water level gets to a certain height in the housing. Is it an electrical resistance type?? I don't know with Fiats.

Normally the housing should have a little drained out the bottom every so often to remove this water. I used to drain about half a cup out every year in my old diesel cars. That was enough to ensure all the water was removed, and some diesel too.

Water in diesel fuel system is very bad for it. Hence the separator.

Years ago , new to Diesels, I was asking advice at a main dealer ( long closed) about changing the fuel filter, whether it needed to be refilled with fuel or would self prime.
The tech who had kindly come to talk to me, said " I just pour the old into the new".

Decent to be offered advice of course, but I have been changing my own fuel filters ever since.

It sounds like you're saying you shouldn't need to have the filter changed at all (unless due) if you get this message?

In my last car (diesel), I covered over 80K miles, and only changed the fuel filter once !

I did drain it every so often though to remove water. WIF and filtration is different.

All diesels should have a drain for water in the separator, and if they don't - maybe they should IMO.

The 'water in fuel' message is NOT filtration dependant, but the WIF sensor has been activated.

To answer Argo's question directly, yes I am saying the filter does not NEED to be changed if you get the message, unless it is due to be done anyway.

NEVER pour old contents into new or leave in the housing. Always remove the contents. Does Stilo have a pump prime device? Either a rubber bulb or plunger????

don't know but try not to use cheap supermarket fuel cause it is c**p