Picasso fan problem please help

[nomis1981]

Hi I have 53 plate citroen xsara picasso 2.0 hdi the problem I have is my fan not kicking in I've changed the temperature sensor and checked the maxi fuses under fuse tray in engine bay but all OK when I have engine running and take off the plug to temperature sensor the fan kicks in witch tells me the relays are fine is there anything else I've missed as going on holiday soon so need this sorted thanks for any help

[myglaren]

Sounds as though you still have a defective temperature sensor.
New ones don't always work.

[nomis1981]

I've changed the temperature sensor again and still doing the same I've been told about a resistor in the radiator shroud that could be the problem so gonna test that with the multimeter

[RichardW]

How do you know it's a problem? I wouldn't have expected an HDi to need fans this weather - they don't make much spare heat. They don't come on till the temp gets to 100 or something, and you'd be unlikely to reach that at this time of year - if you are getting overheating, then you probably have another fault as well. It's possible I suppose that the low speed resistor could be giving trouble meaning that the fans might not come on till high speed temperature (which is about 110).

[GiveMeABreak]

They generally kick in with the Air con / Climate Control on Auto Richard - mine does in this weather and that's after a new condenser and recently repaired at Main Dealers. There was a recent case on the forum with the overheating issue - warning lights on everytime the air con was engaged and went off when switched off. The fan sensor was knackered so car wasn't happy and started overheating.

[GiveMeABreak]

I've changed the temperature sensor again and still doing the same I've been told about a resistor in the radiator shroud that could be the problem so gonna test that with the multimeter

I've heard of the issue from my Citroen mechanic- water gets in under the bonnet near the top of the radiator fan housing and corrodes the wiring in or near the area. Jet washes don't help - so keeping this area coated with some water repellent will help.

[nomis1981]

thanks for your replies ive checked wiring around the temp sensor and fan all seems ok yesterday had front bumper off and checked the fan resistors all ok again i also jumpered the relays and fan kicks in i also took plug off temp sensor fan kicks in on high speed with engine running so shows me all ok there. i did try turning air con on with engine running and heater blower on and i get the light up on button and air con clutch didnt kick in could that be the problem to why fan dont work and how easy are they to change
also is there away to bypass the air con as dont really need it thanks

[RichardW]

Air con likely out of gas. How do you mean bypass? You can probably fit a shorter aux belt if that's what you are getting at? The AC not working won't affect the working of the fan in relation to the engine temperature. Still not sure you actually have a problem - has it overheated or something?

[GiveMeABreak]

I had a loss of cooling on the C5 and it went for a recharge - only to loose it within a day. Ditto 5 visits later to Citroen trying to diagnose the gas leak with dye etc, they finally replaced the condenser and then also found a small leak hidden near the top. Once replaced, my engine fan (which rarely ever kicked in) now comes on frequently with the air con on to dissipate the additional heat generated by the condenser radiator. So if your Air Con is not actually working (or more to the point, cooling ) - there won't be the additional heat to dissipate and hence one reason, like mine, why the fan rarely came on.

As you've already established that the fan is working - I would think that the non-functioning Air Con is the reason why it is not coming on. I think Kwik Fit used to do an Air con re-gas for £50 - but if they couldn't get it at least 10% colder you would get a refund. If it just needs a re-gas and the fan starts working when its really cooling, then you'll know. May be a way to check first without spending on unnecessary parts.

[nomis1981]

im no mechanic but will try things myself before going to one i was told by someone that i should bypass the air con (on another site) but he didnt say how it was done i was so confused myself as ive never heard of doing this.
i think i going to get the air con gassed up to see if it sorts the problem i have (hopefully) ill check kwik fit out as wont use ats as used to work for them and their dodgy ways
i really appreciate all the help and advise you guys have given me about this problem thanks again

[RichardW]

i really appreciate all the help and advise you guys have given me about this problem thanks again

You still haven't actually told us what the problem is......!!

[nomis1981]

my cooling fan wont kick in at all (never heard it on) it overheated once but it has never done it since. i pulled over and waited for it to cool down before starting engine again ive replaced the temp sensor and checked thermostat it was working opening and closing in boiling water ive checked all relays and resistors they are working too ive also taken plug off temp sensor while engine is running and fan kicks in i was asked about if air con was working i checked as never used it since got car and it isnt working the compressor clutch is not engaging im going to test if theres a 12v going to the compressor before i get it regassed

[GiveMeABreak]

If there no gas the compressor and clutch won't engage to stop damage, that's by design. So get it leak checked / gassed first.

[white exec]

Someone needs to have a look at a Picasso circuit diagram on this one.

If control is by a PSA-type thermo switch, there will 3 cables running to it; disconnection should not bring the fans on.
If control is by an thermal sensor and ECU, then disconnection might.

I presume installation is a single fan, and a slow-speed resistor, which will be relay-switched out to give high speed.

Without looking at the diagram, pure guesswork.

[nomis1981]

the temp sensor is 2 pin green plug it has a single fan if i take this plug off the fan cuts in at high speed there are 2 resistors one black 0.8ohms and one grey 0.54ohs ive tested them with multimeter and they are fine there are 3 green relays in a box by the drivers headlight and there ok too im lost what to check next other then getting air con regassed and checking if theres 12v running to it