Only one raditor fan working

[shawnshah]

Dear All,

This is my first post in this forum which I think is fantastic. My question is I had a raditor change and then the mechanic tested the raditor fans, only one fan(located next to the air intake) works when AC is turned on or when the car is getting hot the fan comes up, second one is not turning on.

My question is when does the second fan turn on or is it turned on at a specified temperature or do both the fans turn on at the same time.

power is coming to the fan that we have tested. can some body advise if there is something wrong.

VT owner.

[graham7773]

try turning your air conditioning on when the one fan is working. the second fan should come on then. If it does not, then you may have a fault. According to GM, that is how they are supposed to work.

[Burnout124]

the second fan works when your car is verry hot i tested thin on my car pulled the relay fot the first fan and wated till the car got to 3/4 on the temp gage and then the other fan kicked in

[blacknight]

For my VX, the second fan always came on whenever i started the engine and the second fan comes on when the AC is turned on, i.e both fans running. Had the AC fan replaced few months back as it was a dead unit. Didnt realize that the two fans were different sizes...cars works fine now

[ch1mp]

as far as i know the first fan comes on when your car gets warm, the second fan comes on when your car overheats. This is how most cars work...not sure about commodores tho

[accentstencil]

With the A/C on both fans should operate at low speed then i f the temperature rises to 104 they both switch to high speed. This is according to the Gregory"s manual.
Edit: Just checked and both my fans come on with the A/C

[shawnshah]

thanks for the help fellazz, any suggestions what could be the problem or which part I need to change to fix this.

[VK SL 3800]

Test the relays, dont know where they are exactly in a VT but i think there on the drivers side somewhere in clearly marked box.

[shawnshah]

Thanks dude, I have tracked down the relays,one is a high speed fan relay the other is low speed relay. Dumb question m8 can you please let me know how to check the relays.

[jetboy]

Thanks dude, I have tracked down the relays,one is a high speed fan relay the other is low speed relay. Dumb question m8 can you please let me know how to check the relays.

there is a thread on here to check your relays i'll try find it

[jetboy]

scroll down to ' Cheap6 ' s comment that should help you out as will the whole thread actually
Both Cooling Fan's Not Running? Help

[shawnshah]

Thanks jetboy,

Relays working fine.

I checked with Holden themselves who said second fan will not come on till a certain temperature is reached. That goes for ac as well. second one comes on after a certain temperature when AC is switched on. Your. Views guys

[Mick1988]

First fan comes on when the car gets to operating temperature OR you turn the air con on. Second fan only comes on if the first fan isn't keeping the temperature at a steady, safe level.

[oska]

2 fans

one fans cools the rad when it gets to 104 degrees and stops at 99 degrees

the second one switches on when the aircon gets switched on to cool the condenser

[shawnshah]

Hmmmm I think i need to check couple vt's myself. And some mechanics. Only one fan switches on in my ride when AC is switched on or when the car reaches the operating temperature.

[BlackVXGTS]

ENGINE COOLING FAN LOW SPEED
The engine cooling fan low speed relay is energised by the BCM. The PCM determines when to enable the low speed fan based on inputs from the BCM serial data, Engine Coolant Temperature (ECT) sensor and the Vehicle Speed Sensor (VSS). The cooling fan low speed relay will be turned "ON'' when:
. The A/C request indicated (YES) and either the vehicle speed is less than 30 km/h
- OR -
. A/C pressure is greater than 1500 kPa
- OR -
. The coolant temperature is greater than 104 degrees C.

If the coolant temperature is greater than 117 degrees C when the ignition is switched off, the relay is energised for up to approximately 4 minutes.
If an engine coolant temperature sensor fault is detected, such as DTC 14, 15, 16, 17 or 91.

The cooling fan low speed relay will be turned "OFF'' when any of the following conditions have been met:
. The A/C request is not indicated (NO)
. The A/C request is indicated (YES) and the vehicle speed is greater than 50 km/h and A/C pressure is less than 1170 kPa.

ENGINE COOLING FAN HIGH SPEED
The engine cooling fan high speed relay is controlled by the PCM based on input from the Engine Coolant Temperature (ECT) sensor. The PCM will only turn "ON'' the engine cooling fan high speed relay fan if the engine cooling fan low speed relay has been "ON" for 2 seconds and the following conditions are satisfied:
. There is a BCM message response fault which will cause a DTC 92
. An engine coolant temperature sensor fault is detected such as DTC 14,15,16,17.
. Coolant temperature greater than 104 degrees C.

The engine cooling fan high speed relay can also be enabled by the A/C Refrigerant Pressure Sensor. When the A/C Refrigerant Pressure Sensor determines the A/C system pressure is to high, greater than 2600 kPa, and this will instruct the PCM to enable the high speed fan.

If the low speed fan was "OFF" when the criteria was met to turn the high speed fan "ON", the high speed fan will come "ON" 5 seconds after the low speed fan is turned "ON". "

If both the engine cooling fan relays are "ON", the PCM will turn "OFF" the high speed relay when:
. The engine coolant temperature is less than 99 degrees C.
. A/C request not indicated (NO)
. A/C request indicated (YES) and A/C pressure is less than 2300 kPa.

[shawnshah]

looking at the above i think my VT is is fine.

[shawnshah]

Guys, I like to thank you all for your comments and help. To be honest with you I did not hope many people will come to the help of fella commy lover but commies bring us togather. Thanks fellaz