Technical Seicento sporting fan test
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Technical Seicento sporting fan test
Lets see if we can get your head round this once and for all.
The fan is provided with a permanent live. If you put that to earth, the fuse will pop, although I would suggest that a test light will be less destructive.
The ECU switches on the earth side of the connector. If the ECU doesn't think the engine is hot enough it will not have 'enabled' the earth, hence why the fuse didn't blow.
Its all to do with an electronic 'fact' that its easier to sync an earth than a supply, apparently. I was discussing this very thing with an electronics 'geek' earlier today.
Cheers
SPD
The fan is provided with a permanent live. If you put that to earth, the fuse will pop, although I would suggest that a test light will be less destructive.
The ECU switches on the earth side of the connector. If the ECU doesn't think the engine is hot enough it will not have 'enabled' the earth, hence why the fuse didn't blow.
Its all to do with an electronic 'fact' that its easier to sync an earth than a supply, apparently. I was discussing this very thing with an electronics 'geek' earlier today.
Cheers
SPD
Ok you use any off
a mutlimeter
Halfords screw driver with 12-24v lamp
Halfords screw driver with 12-24v two colour LED
The light should come on on the 12V connector, cause it is always there when the ignition is on.
That does for one of the wires the other is a pig.
First you need to check both earths are good, both inner wings, remove fastner clean till shiny metal copper slip dollops, re-assemble.
Then you need to check the temperature sender is ok, suggest multi meter in situ, cold and hot (after you run the engine).
The ECU will fire (earth) the fan via a high current relay which relay should have a fuse, 30amp say, so you may want to check the relay and fuse. Be careful you can cook things with a paper clip, I'd not let you near my auto with a paper clip, the fuses are expensive BTW...
David (RallyCinq) will help better then me...
Does the fan run i.e. start reliably and run for long interval while it has power when you connect a 12v and earth wire to it, if it will occasionally not start then it is replace time, a new fan is a lot cheaper then head gasket job, unless you like replacing head gaskets.
(some one is gonna tell us this is a new thread.)
Noel
a mutlimeter
Halfords screw driver with 12-24v lamp
Halfords screw driver with 12-24v two colour LED
The light should come on on the 12V connector, cause it is always there when the ignition is on.
That does for one of the wires the other is a pig.
First you need to check both earths are good, both inner wings, remove fastner clean till shiny metal copper slip dollops, re-assemble.
Then you need to check the temperature sender is ok, suggest multi meter in situ, cold and hot (after you run the engine).
The ECU will fire (earth) the fan via a high current relay which relay should have a fuse, 30amp say, so you may want to check the relay and fuse. Be careful you can cook things with a paper clip, I'd not let you near my auto with a paper clip, the fuses are expensive BTW...
David (RallyCinq) will help better then me...
Does the fan run i.e. start reliably and run for long interval while it has power when you connect a 12v and earth wire to it, if it will occasionally not start then it is replace time, a new fan is a lot cheaper then head gasket job, unless you like replacing head gaskets.
(some one is gonna tell us this is a new thread.)
Noel
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The Fan works fine when i test it against the battery..it runs as it should. When i connect the plug back in and run the car up it never works. The temp sensor has been changed and the fan fuse is OK. Im guessing at a shot the wiring going to the fan is faulty ..
Hi
Thanks, but you had a more complete check list
To do
First you need to check both earths are good, both inner wings, remove fastener clean till shiny metal copper slip dollops, re-assemble.
Done the next good
Then you need to check the temperature sender is ok, suggest multi meter in situ, cold and hot (after you run the engine).
Done for the fuse, but the relay may be kaput, the drive from the ECU should be ok it is well reliable, relays can be unreliable, try to see if it will click with 12v to control wires.
The ECU will fire (earth) the fan via a high current relay which relay should have a fuse, 30amp say, so you may want to check the relay and fuse. Be careful you can cook things with a paper clip, I'd not let you near my auto with a paper clip, the fuses are expensive BTW...
Thanks, but you had a more complete check list
To do
First you need to check both earths are good, both inner wings, remove fastener clean till shiny metal copper slip dollops, re-assemble.
Done the next good
Then you need to check the temperature sender is ok, suggest multi meter in situ, cold and hot (after you run the engine).
Done for the fuse, but the relay may be kaput, the drive from the ECU should be ok it is well reliable, relays can be unreliable, try to see if it will click with 12v to control wires.
The ECU will fire (earth) the fan via a high current relay which relay should have a fuse, 30amp say, so you may want to check the relay and fuse. Be careful you can cook things with a paper clip, I'd not let you near my auto with a paper clip, the fuses are expensive BTW...
Looks like this but could be different size and colour like orange.
Try fuse box or engine bay.
Try fuse box or engine bay.
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Hi
My car is SPI and is different...
But you are looking for a broken relay, if they have little circuit diagrams on the cover try the control circuit for a click, no click go to factor with origonal.
If it clicks replace and try next one, dont break one that might be working...
If they all click you need to check with bulb and 12v that the slave circuit closes when the relay clicks.
If all the slaves work, we will have to wait for Rally Cinq...
Noel
My car is SPI and is different...
But you are looking for a broken relay, if they have little circuit diagrams on the cover try the control circuit for a click, no click go to factor with origonal.
If it clicks replace and try next one, dont break one that might be working...
If they all click you need to check with bulb and 12v that the slave circuit closes when the relay clicks.
If all the slaves work, we will have to wait for Rally Cinq...
Noel
The relay is in the engine bay under a black plastic cover above the servo held on with two M5 nuts.
The wire colours going to it are:
Purple= +12v in for fan (Common contact)
Orange/Black= +12v coil feed
Grey/Black= Out to fan (N/O contact)
Green= To ECU
If the fan has been playing up then the relay contacts could have burned (whiskered) so may be unreliable. Change the relay.
The wire colours going to it are:
Purple= +12v in for fan (Common contact)
Orange/Black= +12v coil feed
Grey/Black= Out to fan (N/O contact)
Green= To ECU
If the fan has been playing up then the relay contacts could have burned (whiskered) so may be unreliable. Change the relay.
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Do you have a supply to the relay?
Cheers
SPD
Cheers
SPD
I will find out tomorrow when the car goes to for it's MoT and ive asked them to take a look. Hopefully it wont fail on too much..im a bit concerned that the brakes and new discs that are new and have not had chance to inbed a little and there may be a slight exhaust blow from the front. Other than that fingers crossed it should be okay. All the lights work, horns ok, wipers are fine so its a case of wait to see..:worship:
If you have an old relay. Take the plastic case/cover off it and manualy close the relay. If the fan runs then sensor/ecu cable check for continuity.
The fan is needed for an MoT other wise you may lose the head gasket.
Rallycing is correct it is easy to check there is 12v at the relay socket and at the fuse socket, but the probability was rust at earth or kaput relay, the 25 amps is hard on a relay.
You got two fan relays?
Noel
Rallycing is correct it is easy to check there is 12v at the relay socket and at the fuse socket, but the probability was rust at earth or kaput relay, the 25 amps is hard on a relay.
You got two fan relays?
Noel
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Yes I changed both fan relays...
For the MOT I'd turn the heater to on and the heater fan to max if the rad fan is not operating, just gives about 2kW of cooling while they do the tests with the engine running.
I'd tell them the problem as well, you dont need to scald a MoT personto get a fail.
Was there voltage on both of the relay sockets?
Noel
I'd tell them the problem as well, you dont need to scald a MoT personto get a fail.
Was there voltage on both of the relay sockets?
Noel
