Astra G 1.8CSE Cooling Fans Problem

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AstraOwner

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need help to what may be causing my fans to run constantly as soon as ignition is turned On..this started after i changed a cracked radiator .thermostate was stuck open all the time so i had it replaced aswel.my coolant light stayed on since the radiator change..had car diagnised and a code error P1540-8 came out which is A/C SYSTEM HIGH PRESSURE...both fans are running even when aircon is not switched on...so what cn this be...had few different opinions from these mechanics which is not pointing to one problem..one said its my fan motor thats broken,one said its the bleeding but it was bled correctly,one is saying its my cooling module....please help
 
Last edited:
-Faulty A/C System Pressure Sensor

-A/C System Pressure Sensor harness is open or shorted

-A/C System Pressure Sensor circuit poor electrical connection
 
thechamp said:
A faulty or unplugged coolant temperature switch?
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That could also be it, vehicle go into full cooling mode if the temp sensor goes awol. But op seems to be implying the aircon fan is going full bore not the motor cooling fan?
 
airborne said:
That could also be it, vehicle go into full cooling mode if the temp sensor goes awol. But op seems to be implying the aircon fan is going full bore not the motor cooling fan?
Click to expand...
both fans are running even when aircon is not switched on.
Click to expand...

That is what my Corsa does when the coolant switch wire is unplugged or shorted.
 
thanks guys but my quiry is tht,a new thermostat was put in and it came with new coolant /radiator switch on it...if i unplug this switch while engine is running the management light comes on(orange light with a spanner on it),so j want to believe tht its working properly ..next to the aircon radiator is a switch wich i was told is a aircon switch and one guy told me after tasting it that it doesnt hv voltage ..cn this be causing all fans to run ??
 
is there any other temp sensors apart from the one tht comes with thermostate on this Astra.
 
airborne said:
That could also be it, vehicle go into full cooling mode if the temp sensor goes awol. But op seems to be implying the aircon fan is going full bore not the motor cooling fan?
Click to expand...

temp sesor ,which one is that??
 
Rickster said:
-Faulty A/C System Pressure Sensor

-A/C System Pressure Sensor harness is open or shorted

-A/C System Pressure Sensor circuit poor electrical connection
Click to expand...

Rickster,cn you shed morelight ,where is thi pressure sensor located and the harness
 
AstraOwner said:
thanks guys but my quiry is tht,a new thermostat was put in and it came with new coolant /radiator switch on it...if i unplug this switch while engine is running the management light comes on(orange light with a spanner on it),so j want to believe tht its working properly ..next to the aircon radiator is a switch wich i was told is a aircon switch and one guy told me after tasting it that it doesnt hv voltage ..cn this be causing all fans to run ??
Click to expand...

If you have a multimeter, uplug the wire going into that switch, test the resistance across the two terminals and see if you don't pick up a short circuit.
 
thechamp said:
He means the temperature switch I think, the sensor is the one that supplies the temperature gauge with a signal.
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ok i will have it tested..so you mean the two pins in the switch one should show voltage ?is it done while ignition is ON....if may ask,doesnt these engines have a seperate temperature sensor for the engine apart ftom the coolant sensor. .if it has then where is it located
 
Google for the Haynes service manual, must be one floating around in pdf, that will make your life so much easier.
 
AstraOwner said:
ok i will have it tested..so you mean the two pins in the switch one should show voltage ?is it done while ignition is ON....if may ask,doesnt these engines have a seperate temperature sensor for the engine apart ftom the coolant sensor. .if it has then where is it located
Click to expand...

Don't worry about the voltage, just test for a short circuit on the wires with the ohmmeter function, if there's a short on the wires the fans will run all the time, remove the plug and test the wires across the terminals. After that test the switch on its own across the terminals, you should get some resistance, you should get between 2000 and 3000 ohms or somewhere, it differs between cars, if it tests open circuit then the switch is faulty. The resistance should also differ when the switch is cold and hot.

Test with the car off for safety.
 
thechamp said:
Don't worry about the voltage, just test for a short circuit on the wires with the ohmmeter function, if there's a short on the wires the fans will run all the time, remove the plug and test the wires across the terminals. After that test the switch on its own across the terminals, you should get some resistance, you should get between 2000 and 3000 ohms or somewhere, it differs between cars, if it tests open circuit then the switch is faulty. The resistance should also differ when the switch is cold and hot.

Test with the car off for safety.
Click to expand...

will see to tht....kinder busy this week
 
Hie guys ,i took the car to a local tech,and he suggested i get new cooling module,....does this sound right to you gurus...
 
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