Radiator Cooling Fans Running Constantly

[madwelshman]

Hey folks,

I've been working on my mates Berlingo van helping him put it back together again.
Anyway, when we turn the key to the ignition on position, the cooling fans (on the radiator) start running straight away, at full speed and don't stop. we've tried disconnecting them, running it to 1/2 way up the gauge then reconnecting them and as soon as the plug is connected again, they start and just don't stop until you turn the engine off.

The van is a 51 plate 1.9 n/a diesel. DW8(?) engine I believe.

What do I need to be checking/looking at
Any suggestions greatly received.

Thanks
Will

[darbuck]

Sounds like a fan switch stuck new switch should sort it

Sent from my ALCATEL ONE TOUCH 903 using Tapatalk 2

[madwelshman]

Cheers Darbuck,

I didn't see a coolant switch on the rad, but there must be one there somewhere so I'll have another look today.

Will

[RichardW]

The sensor is on the thermostat housing - depending on the exact van/engine, there might be one or two sensors. If it is caput, or unplugged, the fans may well run all the time. Is it a Mk1 (small lights) or Mk2 (big lights)?

[madwelshman]

Hi RichardW,

It's a 51(2001) MK1 1.9d.
There's only one sender on the thermostat housing and it doesn't make the fans stop when I unplug it.
I didn't think the sender was the problem though, because the temperature gauge on the dash still works.
Am I right in saying that the ECU controls the fans on info it receives from the single temp sender?

Will

[madwelshman]

Also, does anyone know what these wires are for, or where they should go?
They were just tucked inside the protective casing that surrounds the wire to the fuel stop solenoid and were just two bare ends.
I bared the ends of them to check for any voltage both with and without the ignition turned on. One of the two does
energise (12v) when the ignition is turned on.

[madwelshman]

HELP!!!!
Today, we got a new temperature sender (the one on the thermostat housing) and tried that.
But, when we turned the ignition on, the fans came on straight away (as before) and went off again when the ignition was turned off again.
The sender is a green one with two wires.

So, any suggestions what to look at next, PLEASSSSSSSSSE! I'm starting to pull my hair out now.

Has anyone got a wiring diagram for the cooling fan circuit?

Thanks in advance
Will

[RichardW]

Looks like someone's been messing with it - that is not standard wiring at the stop solenoid...

Re the fans, you need to get it on a Lexia and see what it thinks is going on. Possible the wire is broken somewhere. Interestingly, service.citroen says that Mk1 DW8s should have 2 sensors - given that yours only has one, and the solenoid wiring has been butchered, then I wonder if it's had an engine change to a later unit, and the fans are not connected to anything....

[madwelshman]

Could it be because it's a 2001(although being a '51' could be early 2002) model/reg that it's got the single sensor and not two. I'm assuming that the mk2's went to a single sensor.
My other option, is find a radiator of a diesel Berlingo/Partner with a sensor on the rad and just wire that in. That's probably what I'll do if I can't suss this out, or put a thermostatic control on the top hose.
It's just bugging the hell out of me.
Are the fans controlled/switched by the ECU, or controlled directly from the sensor to the fan relay?

[madwelshman]

I think we've found the problem.
One of the pins in the ECU on the engine loom side has come out and the plug is damaged.
It appears that when my mate jet washed the van off before he stripped it down, water got past the waterproof seal on the engine loom plug (ECU end) and has caused damage to the plastic of the plug around about 3 pins and when the plug has been removed from the ECU, it's pulled the pin out of the ECU.

Soooooo, a mate who's an electronics whiz is going to look at repairing the ECU and changing the plug/damaged socket in the plug.

But if he fails, what's the score with replacing the ECU?
I'm guessing they have to be re-programmed, Is that right?

Will