Technical Marea Weekend 1.9 JTD FAN RELAY FAULT

[anfirmor]

I have a y reg Marea Weekend 1.9 JTD with A/C and climate control. The radiator fans never kick in and there is a dash warning light on permanently. The brain is claiming "fan relay fault" (checked by son with ECU reader) but I have checked the relays on the bench and they all seem OK (energise and contacts). Also linking out the relay contacts in the connector by the battery bring the fans on so it must be a signalling relay coil signal) fault.

There is no sign of a radiator thermostat so I am left wondering what to check next. I believe the fans can be forced on with a Vag type lead and FIAT ECU CHECK but I am a little confused as to how cooling fan system works. The workshop manuals I have found don't seem match my car exactly

Any help or advice would be much appreciated.

 

[anfirmor]

OK. I have finally got FIAT ECU SCAN to connect to my Marea (MAREA 01 JTD 110 CF3). There are two fault codes stored as below.....

P04841 COOLING FAN (2) FATAL
P00480 COOLING FAN (1) FATAL

the description basically states....

NO SIGNAL FROM SENSOR

Also I cannot get the fans to turn on using the force output feature in FIAT ECU SCAN.

Does anyone out there have a clue to which sensor is being referred to and why it would prevent forcing the fans on via FIAT ECU SCAN.

many thanks

 

[stylers]

check that the fan relays have a 12V feed at the coil terminals (85 or 86). this supply is fed via a seperate fuse. that second code doesn't make sense, probably should be P0481. disregard the "no signal from sensor" description..

 

[anfirmor]

Problem solved.

Took the methodical approach that I should have in the first place. A bit of belling out turned up a rotten (pinched) wire close to the multi-way connector that clips to the fan relay box. the 12V coil feed in fact. Checking coil connection voltages with this fault was made a little confusing as I was reading about 3.5V on both sides of the coil.
I presume that this is a backfeed from the ECU which, I guess, sinks the relay coil -ve and must have some current sense circuitry inside.

Anyway thank you to all who helped with this problem. No more fault lamp and error codes cleared at last

Another nastier fault now but unrelated so will post new thread.

thnks again