Xsara Picasso cooling fan not running at high speed

[matjam]

Hi All,

I'm hoping some kind soul can help me.

I have a 58 plate Xsara Picasso, 1.6 diesel.
Just recently it's been having problems with the air con, so it's had a new condenser fitted and a re-gas.

If the car is stationary on the drive and you switch on the air con, the compressor clutch clicks in, and the radiator cooling fan kicks in too.
From what I understand the cooling fan has two speeds, and it is running in 'low speed' mode at this point. Air con blows nice cold air.

My problem is when you then drive the car. After a few mins you can tell that the air con is no longer blowing cold air.
I have stopped and looked at the cooling fan to find it no longer running.

So is my problem with the switch over to high speed mode not working?
I've read several posts on this, mainly saying things like:

• Check resistor 'x'
  Check temp sensor 'y'
  Check relay 'z'

But I have no real way of testing these things. I can unplug things and plug them back in if I know where they are.

Are there any wiring plugs near the fan that could have been knocked/not plugged back in properly when the garage replaced the condenser?
Would OBD help?

I feel a trip to a garage coming on, but would like to steer them as much as possible into what the fault might be.

Thanks in anticipation.
Matt

[RichardW]

Welcome Matt

The AC is probably either disengaging becuase the pressure is too low or too high. Probably worth a trip back to the garage to get them to hook the gauges up and watch what the pressure is doing. I suspect they may have overfilled it, and it is tripping the high pressure cut out, then when it cools back down, pressure drops and it will re-engage for a while. If it looks normal on the gauges, then you need to hook it up to Lexia diagnostic computer to see what is going on - you may well be able to test if the fan will run at high speed using this as well. Might be someone near you with a Lexia can plug it in, see http://www.frenchcarforum.co.uk/forum/v ... 19&t=29178" onclick="window.open(this.href);return false;

[Lighty]

If you are traveling forward, the A/C should be cold regardless of the fan, this reinforces that you do not have a fan fault, but a pressure fault.

[matjam]

Thanks both for your replies.
So it looks more likely that a trip back to the garage is in order.

Out of interest, if high pressure is the problem, how long would it take to trip the high pressure switch?
I only ask as I've had it running ok on the drive for over 10 minutes.

Oh, and 'Lexia' - is that an OBD II diagnostics thing?

Thanks again for your help.

[Hell Razor5543]

The Lexia is a far more powerful diagnostics tool then a generic OBD reader, and Citroens don't normally respond to generic readers. The Lexia isn't just a reader, it can (in the hands of an expert) tell you everything that is going on with the car.

[matjam]

Ok, here's an update.
I took it back to the garage. They got their charts out and they state that the amount of gas for a Xsara Picasso is 700g, which is what they'd put it.
The pressures looked ok.
In order to rule out the pressure problem, he's reduced the gas so that the system now has 450g in it, and we were going to so how that went and if it was running ok, then top it up bit by bit.

However, not long after leaving the garage the same thing happened, it just stops blowing cold air.

So, it does not look like a pressure problem but it could still be a faulty pressure switch. Or some other sensor.

It's looking more likely that it'll need hooking up to full diagnostics.

Cheers,
Matt