Technical I'm it's biggest FAN

[Renegade_8]

Pic of our Weekend attached. It's a great car a 1.8 ELX reg Sep 2000 I got it 1 year old and it's given very little trouble. I would appreciate some help though with the engine cooling fan.
I have already got a lot of help off here as a lurker by searching the archives, but would like a bit more over and above. Last Thursday in a jam on the M25( so no change there) the temp gauge started to climb. Between turning the heater on full and opening the windows and the amount of forward motion, no harm done. I have the Brava/Bravo Haynes manual which has zero info here. Running the car stationary on our drive at home confirms the fan is not cutting in. The car has only one cooling fan which is controlled by the ECU and the aircon switch, this is mounted in the filter and I know that works because it gave trouble a month ago and was cleaned and was turning the engine fan on on a/c coolant pressure. The thermistor must be OK as the gauge works. I checked fuse no 6 inside the car, it's fine then I opened the relay box in front of the battery (1 x 10mm bolt + thanks for this info on here.) I have no idea which relay does what. There are 4 small oblong ones 2 red 2 black and a big square black one. I took all 4 small relays out and checked them with a DVM, all are 80 ohm coils and open circuit power off 50 milli ohms power on. Some had a little corrosion on the spade terminals but nothing to worry about. I failed to get the big square relay out, it seems to be mechanically latched but I cant see how, is this the fan relay? if it is how do you get the thing out???? I also tried to disconnect the loom from the fan to test it but the 2 connectors will not move, again are they latched in some subtle way I cant see? The seem to have small S shape bit of plastic sticking up, but pushing and pulling this in all logical and illogical directions had no effect. It would be nice to get a steer rather than resort to violence which can end in tears.

 

[Hellcat]

Sounds like you're very close to your target.

You say the spade contacts were a little corroded? Mine were too but the problem was on the underside of the relay housing where the wires connect to the female connectors. Replacing the housing with crimp on connectors fixed the problem.

I was about to go outside and take a photo when I realised that was on the 105JTD which I have sold.. Needless to say the guys at FAST knew exactly where to look straight away. Took the relay housings apart (yes they have some sort of connector block between them) and I could see for myself how corroded some of the wires were.

 

[Renegade_8]

Thanks for that,from memory ( dark outside) that relay box is a scary rats nest! I guess you can remove the relay sockets from the top, I imagine you cant remember which is the fan one as I dont want to pull them all out, (no point looking for trouble, adequate quantities will always find you

 

[Hellcat]

Sorry no can't remember. Doesn't it say on the top which does what? That might have been my gf's dad's Alfa 156 which has a similar placed set of relays.

Might still be worth whipping them all out and rubbing a bit of glass paper over the contacts.

 

[Renegade_8]

Ok , and thanks a lot for super quick answers.

 

[Renegade_8]

Thought I would post again for your info really. The problem actualy was the fan, the clue was in the question and the reason the terminals on the fan wouild not move was they were jammed solid with corrosion, long story short here are pics of the back and front of the terminal moulding on the fan, the one that is gone is the switched earth, the +12 v feed was still hanging by a thread. I could save this fan by fitting new flying leads to a terminal block but I think I will just buy a new one as I dont want to have the car in bits and then hit a big problem with my "unauthorised modification.

 

[Renegade_8]

More to this sage, I got a new fan at Thames Fiat, so called because once your car goes in the workshop there it sinks without trace, they gave me a deal to match the internet price. When I got it home it turned out that the corroded terminals were just a feed to a 0.3 ohm N watt dropper resistor, so I just swapped this bit out and now the fan cuts in on the air con. I could not get it to cycle on engine temp even with the bonnet closed the temp gauge just stayed steady at just over the centre of the scale. The Haynes manual gives the resisatance versus temp values for the thermistor and I wonder if any forumites have ever used this to "spoof" the ECU and so test the fan? There are 3 pins on the connectoron top of the thermistor, does anyone know why, and which 2 the resistance appears across? I am going to try with a 100 ohm fixed R and a 2K pot sometime. I did e-mail Thames Fiat to see if they have the kit to do this, but the e-mail sank without trace.

 

[johnson550]

my temp gauge is about the same I sat one day when the outside temp was about 28 or 29 and it took about twenty mins before the fans came on that was after parking up after a run out thought they were never gonna start up so it may worth waiting a bit longer see if they fire up

Bill

 

[Renegade_8]

Great news all followers of this thread. The wife got back from a circular tour of the relatives today and had to go shopping, while the car was being unloaded I left it idling.(This gave plenty of time for heat soak!) After driving home with 2 of us in it plus the 200 kilos she picked up to see us through the week and a 22C ambient temp I was able to see the fan cut in both on the a/c and without, and the temp gauge remained in the middle where it belongs. This is very odd as the wires direct to the motor which would allow by-passing the dropper R imply there isa full speed as well, and why did that not cut in on the M25, however without a circuit and some info on the ECu this is as far as I can get and I dont expect any problems in service. I will get a 0.3 ohm 20 watt and fit it to the old moulding refit that and sell the new fan on E-bay.

 

[jug]

well done, there's nothing like a bit of investigation.

I will get a 0.3 ohm 20 watt and fit it to the old moulding refit that and sell the new fan on E-bay.

thats like something i'd do

but next time avoid fiat at all costs, or it'll cost ya