Hi speed cooling fan trouble

[Brett_jjj]

The gregorys says that the lo fan is controlled by the BCM and ECM and the Hi speed controlled solely by the ECU.That explains why theres a low speed fan test in the BCM menu on the tech 1 as well as in the engine /ECU menu.Im gonna try another fan motor in the morning ,see what that shows.Checked the fusible links all ok. Thanks for the help fellas,I will post how I get on with another fan motor.

 

[Cheap6]

You might like to try the tests I suggested in a recent post in VT-VX. VS and VT/VX are very similar in how the fans operate.

http://forums.justcommodores.com.au/1443446-post11.html

 

[Brett_jjj]

Thanks ,will try that.

 

[admir87]

when aircon is switched ON, only the low speed fan is turned ON...
also low speed fan will turn on when the coolant temp sensor detects 104C

then low speed will switch off once coolant gets to below 99C

high speed only comes on if coolant temp ever gets to over 110C

low speed is controlled by the ecu, which gives a signal to the bcm to turn the relay ON
high speed is controlled solely by the ecu.

get yourself some jumper wire, disconnect the fan connector and connect the low speed straight onto the battery and an earth for the negative on the connector. make sure that low speed comes on

as for the high speed, you need 12v to both low and high speed on the connector and an earth for both negative connectors ( you cant just put 12v on the high speed side of the connector, it doesnt work like that). See if high speed works

once you rule out the fan motor go to the high speed relay, swap it for a spare,(pretty sure the highbeam or heater or something is the same relay as the high speed fan) once you swap it, disconnect the coolant sensor plug and see if low speed then high speed kick in now

then it could be anything from ecu to coolant sensor

sorry for the ramble

 

[Brett_jjj]

I will retest the fan like you have said with both terminals getting the 12 volts,and the other 2 earthed ,I did one at a time and it didnt look like the fan changed speed,now I know why. Thanks heaps to everyone for all the help,will post what I find out tomorrow.

 

[Cheap6]

as for the high speed, you need 12v to both low and high speed on the connector and an earth for both negative connectors ( you cant just put 12v on the high speed side of the connector, it doesnt work like that).

With the low speed fan relay (5 pin) in place, both high and low speed windings will be switched by the high speed fan relay. That's why the 5 pin relay is used (and why I suggested it be in place when testing).

 

[Brett_jjj]

Following Cheap6's link I tried to jumper the larger relay pin socket no's 87 and 30.Nothing, except the ignition stays on when the key is turned off.Triple checked the pin numbers and connections, all ok.And when I connected the large relay pin no 86 to earth ,sparks showered everywhere.I hope it hasnt fried anything,also the small (5 pin)relay is numbered from 1 to 5 not 86, 87 etc,so I left it alone not knowing what each terminal is for I didnt jumper anything on it.I tried connecting both terminals on the fan connector to 12 volts and both earths,When one live wire is removed it drops to lo speed, so the 2 speeds are working,although it does a fair bit of sparking when the jumper wires are connected/disconnected to the pins.The jumper wires I used are fairly heavy gauge and they were getting hot when the fan was running.Im going to get another fan later so I can try it,I will post what I find.I dont want to take it to an auto electrician,most of em just like to bypass the original wiring and relays and run new wiring and relays etc,which makes a mess of the wiring in my opinion.Id rather have the original stuff fixed.

 

[admir87]

ye the sparks are normal from when you connect the motor on both terminals, happened to me too....
so your fan is fine....

have you replaced your high speed relay?

and when you pull the connector off the coolant sensor, are you getting 12v to the high speed relay?

 

[Brett_jjj]

Theres 12v available to pin sockets 86 and 30 with the key on, on the hi speed relay.With key off there is 12 v available at pin socket 30 only.
The small lo speed relay has 12v available at pin sockets 5 and 1 with key on,and 12 v available at pin socket 5 only with key off.I havent had a chance to check the voltages available at the pin sockets when the sensor wiring is removed and engine running.Will do that in the morning.I checked the hi speed fan relay terminal sockets though whilst commanding the hi fan on and off with the tech 1 and there was no difference to any voltages on any pin sockets.
******** me picked up a spare VN fan today instead of the VS one I have,I didnt even take any notice of it being different until I got back into town.I will go get the VS one in the morning.But today the fan was working on 2 speeds when I used jumpers to test it though,so it might not be that anyway.Ive also tried about 5 different large hi speed relays, and swapped over the small lo speed relays,same same.The Tech 1 says that the BCM and ECU/PCM are commanding Hi fan on,so I just dont know.This one has got me stuffed.It might be a job for a holden stealer er dealer.

 

[admir87]

i got a feeling that there is no need for the high speed fan to come on at all, thats why its not switching on (the temp isnt getting over 110C )

once you do the, engine running and disconect the temp sensor connector, test, you will see if both are working.... low speed switches on, then a couple seconds later high speed switches on.