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Thermo Fan Issues

Kee07

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Hi all need some help on my VX, first of all is the thermo fans ive checked all plugs and relays but only the low speed fan comes with or without the A/C on the high speed fan never comes on ive changed the Coolant Temperature Sensor hasn't done anything i checked and its got power but no earth ive swapped the plugs so now its only the high speed fan that comes on and not the low speed fan im in 2 minds of taking it to an auto electrician or bridging both fans so they both run whenever needed im worried it will be to much for the 1 relay, also noticed that its been using a bit of fuel lately I use 98 only and at half of tank ive only done 140kms if anyone could help or give any advice it will be great thanks.
 

Vin999

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Hi all need some help on my VX, first of all is the thermo fans ive checked all plugs and relays but only the low speed fan comes with or without the A/C on the high speed fan never comes on ive changed the Coolant Temperature Sensor hasn't done anything i checked and its got power but no earth ive swapped the plugs so now its only the high speed fan that comes on and not the low speed fan im in 2 minds of taking it to an auto electrician or bridging both fans so they both run whenever needed im worried it will be to much for the 1 relay, also noticed that its been using a bit of fuel lately I use 98 only and at half of tank ive only done 140kms if anyone could help or give any advice it will be great thanks.
Only low fan comes on with a/c, not high fan which comes on when dangerous high temp is reached and both are on if a/c is also on. Also low fan is bcm controlled and high fan is ecu/pcm temperature controlled from cts.

Try switching the relays around in bay for fan and taking 1 off at a time and or wire bridging relay sockets between the 2 to test operation.

If you disconnect tps and turn engine on you will get an engine light on dash and low fan will come on in a few secs followed shortly by high fan to see if both fans work.

Changing cts idling you will not see any fans on as you need high temps after driving.

As to your fuel usage perhaps check/test/renew 0xygen sensor as that can make ecu change idle/power/fuel usage
 

Kee07

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Okay with the A/C on only the low speed fan comes the high speed doesn't I mocked around with the plug and now only the high speed fan comes with A/C on and not the low speed even if I don't have A/C on and motor needs to cool down the high speed comes on but not the low speed idk what to do ive swapped relays around everything hasn't done any difference im looking at getting the mace tuned PCM for it anyone It might be the pcm playing up or something im not sure im far from any type of mechanic haha, As for the O2 Sensors might take them out and see if they are dirty or anything might just get some new ones it had a quarter to empty ( Only got 220kms out of a full tank of BP 98) so I got fuel and it kept on making the pump click so I had to slowly pull the handle on the pump ( happens everytime I get fuel ) and filled it to where I could see fuel at the top of the neck and the pump said I only put in 30 litres which is weird because I thought they came out with 75 litre tanks.
 

Vin999

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Okay with the A/C on only the low speed fan comes the high speed doesn't I mocked around with the plug and now only the high speed fan comes with A/C on and not the low speed even if I don't have A/C on and motor needs to cool down the high speed comes on but not the low speed idk what to do ive swapped relays around everything hasn't done any difference im looking at getting the mace tuned PCM for it anyone It might be the pcm playing up or something im not sure im far from any type of mechanic haha, As for the O2 Sensors might take them out and see if they are dirty or anything might just get some new ones it had a quarter to empty ( Only got 220kms out of a full tank of BP 98) so I got fuel and it kept on making the pump click so I had to slowly pull the handle on the pump ( happens everytime I get fuel ) and filled it to where I could see fuel at the top of the neck and the pump said I only put in 30 litres which is weird because I thought they came out with 75 litre tanks.
Things sound not quite right and you’re confusing yourself talking about PCM and Mace and swapping fan plugs.

Firstly air con low fan on passenger side is controlled by BCM, High fan on drivers side is controlled by the ECU. The ECU will trigger the high fan when coolant reaches over 100/104C from the CTS reading.

The low fan will only come on with a/c on when driving or idling, if coolant temp hits over 100C then high fan will come on as well and turn off once temp goes below 100C and back on if you don’t move and get cool air thru radiator. So both fans will only be on when a/c on and high temp over 100C from memory it could be 104C. High fan has nothing to do with a/c and BCM

To simply test fans, disconnect coolant temperature sensor, turn on ignition and start engine and let it idle, you will have engine check light on dash, then shortly low fan will come on followed about 15 secs later by the high fan and both fans will be on. The ECU turns fans on to cool engine with the engine warning light due to not receiving temperature reading so thinks engine/coolant has reached boiling stage. Most times even at idle with a/c on and a stinker of a hot day, you will never hear or see the high fan come on unless radiator/coolant is overheating or cactus coolant temp sensor so most people think the high fan doesn’t work.
if doing that test both fans are on while idling with the CTS plug off then they are both ok along with the ECU.
 

Vin999

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As for the O2 Sensors might take them out and see if they are dirty or anything might just get some new ones it had a quarter to empty ( Only got 220kms out of a full tank of BP 98) so I got fuel and it kept on making the pump click so I had to slowly pull the handle on the pump ( happens everytime I get fuel ) and filled it to where I could see fuel at the top of the neck and the pump said I only put in 30 litres which is weird because I thought they came out with 75 litre tanks.
Your fuel drama probably is a dodgy fuel sender unit or the fuel gauge on dash or BCM playing up as the dash temperature gauge and fuel gauge controlled by the BCM are affected when your coolant temperature sensor is on the blink/cactus.

The 30 litre on your fill up is about half a tank on the car.... getting 220kms for a full tank is not right, so indicates a possible dodgy gauge/sender unit. After the first click filling up, the other clicking is normal as some pumps are very sensitive when filling near full tank as there is no more room left in tank and air escaping pushes petrol up to quickly and pump clicks of, so go easy on the trigger after 1st click.

To test tank, run car down low to the low fuel warning with 5 litres fuel left in reserve. Fill tank up immediately and see how many litres to top of filler neck and should be around 70 litres. Then check your gauge reads full, set your trip computer to zero and then see how many kms travelled when gauge reaches half a tank. If less than 300kms travelled then your dash gauge or tank sender unit is cactus.
 

Kee07

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Your a champion mate thank for your help so essentially there's actually nothing wrong with the thermo fans its just me thinking there is as you said the high speed fan only comes when the car is overheating or temperature is over 100c even on a 40c day while idling or driving it just be the low speed fan on.
 

Kee07

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I've changed the CTS so I'll try running the tank until its almost dead empty fill it up and go from there I have a funny feeling it might be the fuel gauge, if so how would I fix the fuel gauge does that mean replacing the whole cluster or not
 

Lex

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I've changed the CTS so I'll try running the tank until its almost dead empty fill it up and go from there I have a funny feeling it might be the fuel gauge, if so how would I fix the fuel gauge does that mean replacing the whole cluster or not
Usually its the sender on the pump in the tank in the vx.
 

Vin999

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I've changed the CTS so I'll try running the tank until its almost dead empty fill it up and go from there I have a funny feeling it might be the fuel gauge, if so how would I fix the fuel gauge does that mean replacing the whole cluster or not
Good idea with a few fillups and see how things go
Chances are as @Lex pointed out, its the tank sender which can be tested without buying anything before knowing, not many gauges/dash break down from my experience, more so electrical bugs with bcm that can playup from dodgy sensors like CTS.
Might be worth $ a trip to electrician after just to test wiring, unless you can do it yourself... it might not be sender or gauge
 

Kee07

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Cheers mate only one way to find out when I get a chance too plus the money side of it especially with Christmas coming up want to do a few other things to the car anyway thanks for the help buddy appreciate it
 
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