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Technical Faulty electric fan (radiator)

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Technical Faulty electric fan (radiator)

P dot co dot

P dot co dot

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I don't think my radiator fan is working when it's supposed too. Should it turn on when the temp gauge goes over halfway? or when the gauge enters the red section?

The fan doesn't seem to come on at all (I know its cold at the moment but yesterday I let the heat get up to about 3/4's before letting it cool down again to see if it would start the fan)

Now the fan works if its wired directly to the battery. I've had the relays off and properly tested with 12v bench supply and multimeter. They click when voltage applied, have internal resistance of 70 ohms. The maxifuse appears to be fine.

Finally I disconnected the coolant temp sensor with the engine running and rather than the fan kicking in straight away it took a few minutes. When it did start it would be going on for a few seconds and off randomly. I plugged the sensor back in (showing half way on temp gauge).

Is the ECU giving the wrong values to the relay?

Thanks
 
P dot co dot said:
I don't think my radiator fan is working when it's supposed too. Should it turn on when the temp gauge goes over halfway? or when the gauge enters the red section?

The fan doesn't seem to come on at all (I know its cold at the moment but yesterday I let the heat get up to about 3/4's before letting it cool down again to see if it would start the fan)

Now the fan works if its wired directly to the battery. I've had the relays off and properly tested with 12v bench supply and multimeter. They click when voltage applied, have internal resistance of 70 ohms. The maxifuse appears to be fine.

Finally I disconnected the coolant temp sensor with the engine running and rather than the fan kicking in straight away it took a few minutes. When it did start it would be going on for a few seconds and off randomly. I plugged the sensor back in (showing half way on temp gauge).

Is the ECU giving the wrong values to the relay?

Thanks
Click to expand...


Your relay - 70ohms on the coil was it? What about the resistance on the high current side?

The Fan will kick in after about 30seconds iirc, as the car questions the plasuability of a failure
The fan should kick in when the guage is above half way

Mine kicks in at half way after a motorway blast and i suddenly pull off and stop, it'll kick in then
If the guage goes over half way, put the internal cabin heater on hot - Speed 4 and point the heat out the windows so you dont cook
I suspect there is a broken wire / poor connection somewhere causing the fan to not power up on request or properly

Ziggy
 
Last edited:
Yes 70 over the coil. Well 72 I think to be exact (think they're rated 50~120). Tested the other relay and get 73 and I've swamped them over to no effect. The resistance over the switch was 0.3 (multimeter set to 200) and goes to 0.00 (multimeter set to 2k) Which I believe is a correctly working relay.

At the weekend I'll unplug the coolant sensor again and leave it a little bit longer. When the fan randomly starts I don't notice the loud noise I used to when the fan used to work. But that could be down to it not staying on for long enough (seems to go on for a second and off almost straight away).

I'm not too worried about it overheating at the moment as the gauge doesn't go above halfway unless I am trying to create those conditions. Summer however will be a different question!

I have cables and multiscan software on my laptop. Is there anything I can monitor with that?

I hope its not a wire! :( could be very hard to track down a break
 
P dot co dot said:
Yes 70 over the coil. Well 72 I think to be exact (think they're rated 50~120). Tested the other relay and get 73 and I've swamped them over to no effect. The resistance over the switch was 0.3 (multimeter set to 200) and goes to 0.00 (multimeter set to 2k) Which I believe is a correctly working relay.

At the weekend I'll unplug the coolant sensor again and leave it a little bit longer. When the fan randomly starts I don't notice the loud noise I used to when the fan used to work. But that could be down to it not staying on for long enough (seems to go on for a second and off almost straight away).

I'm not too worried about it overheating at the moment as the gauge doesn't go above halfway unless I am trying to create those conditions. Summer however will be a different question!

I have cables and multiscan software on my laptop. Is there anything I can monitor with that?

I hope its not a wire! :( could be very hard to track down a break
Click to expand...


MEs can do a Fan actuation test
The fan then should spool straight into life
it confirms
A - Wiring for the fan is good and the fuse / relays is there

If there is a break in a wire, it'd probably be easier to get a donor plug for the ECT and join into the ECU wiring as close as possible, i'd test first paperclip time :)

ziggy
 
Ill have a go with MES when I get in. I guess I need to connect to the ECU module.

You lost me a little towards the end. ECT? and what am I testing with paperclip?

Thanks
 
P dot co dot said:
Ill have a go with MES when I get in. I guess I need to connect to the ECU module.

You lost me a little towards the end. ECT? and what am I testing with paperclip?

Thanks
Click to expand...

Yes log into the engine side of the software
Then go into actuation test in the tabs at the top
You can then scroll down to the 1st speed fan test
If you have Ac you can use speed 2 if required

ECT = Engine coolant temperature (sensor)

Paperclip is to allow testing of the harness from a disconnected ECU wiring :)
thats what i use or improvise with :)

Ziggy
 
Ive hooked the car up to MES and done the actuator test for the fan (Speed 1 as no AC).

The fan doesn't spin but you can hear the relay click.

I'm still not sure what to do with the paperclip/connecting to the ECU?

Thanks
 
If you don't have overheating problems, the fan is working properly, keep in mind logic of the ECU: if you run the engine with temp sensor disconnected, the ECU compare the value with a plausible one (i.e. impossible that the value of the sensor decrease with the engine running) one and probalby actuates a recovery strategy and turn on the fan.
 
Disconnect fan and stick 12v on it. see if it spins, if so, likely problem between relay and fan connector.
If it doesnt spinn with 12v, or kicks in and out, then suspect brushes in fan. Probably easier to replace fan if no spin.
 
I have disconnected the fan and wired directly to the battery and like you say, it kicks in and out. So annoying as the fan is only 2-3 years old! does anyone else have problems with their fan?

Guess its time to look for a new fan.
 
P dot co dot said:
I have disconnected the fan and wired directly to the battery and like you say, it kicks in and out. So annoying as the fan is only 2-3 years old! does anyone else have problems with their fan?

Guess its time to look for a new fan.
Click to expand...
Yup, thats the fan itself. It is unusual for it to fail in such a short time, but not unheard of.
At least there are plenty at the scrapyards.
Probably easier to replace than trying to fix.
 
I made some better wires to bridge the fan and this time the fan turned like normal when wired directly to 12V. Not sure if the motor was seized or what but now when I simulate the fan test on fiat multiscan software it also works. When I run the fan test I hear the relay click, fan turns on, click, fan turns off, click, fan turns on, click, fan turns off. Is this correct or should it only spin to life once? As mine does it twice (in about 5 secs)
 
P dot co dot said:
I made some better wires to bridge the fan and this time the fan turned like normal when wired directly to 12V. Not sure if the motor was seized or what but now when I simulate the fan test on fiat multiscan software it also works. When I run the fan test I hear the relay click, fan turns on, click, fan turns off, click, fan turns on, click, fan turns off. Is this correct or should it only spin to life once? As mine does it twice (in about 5 secs)
Click to expand...

Thats correct on the actuation test
it'll activate it twice for about 5seconds

It may be it was seized, a quick hand spin free'd it and now it work okay for now

If it gets upto temperature and stays with the fan kicking in for about 30-60 seconds and goes off

Then you may have fixed it

Just keep an ear out for it

Ziggy
 
P dot co dot said:
So the other day I was sat in traffic with the needle at halfway on the temp gauge. I hear the fan kick in for about 30 seconds! :D

So it appears the actuation test has fixed the seized fan! Very happy
Click to expand...

Its probably a good idea to dribble a few tiny drops of oil into the bearing at the back of the fan :)

With the engine cold overnight that is - Dont do it hot ffs....

But it may be worth over winter plugging in once ever 2 months to ensure its still spinning
You find over winter the fan doesn't spin much, fills with water/salt/grime and seizes up

Ziggy
 
Ziggy122 said:
Its probably a good idea to dribble a few tiny drops of oil into the bearing at the back of the fan :)

With the engine cold overnight that is - Dont do it hot ffs....

But it may be worth over winter plugging in once ever 2 months to ensure its still spinning
You find over winter the fan doesn't spin much, fills with water/salt/grime and seizes up

Ziggy
Click to expand...

or plug it to mes and start it
 
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