Fan's not starting up

[mattcooper]

Hey
I've read a lot of threads about this on the forum however am slightly confused by it all.

I've noticed my fans just don't boot up. Even after 15 mins of running with air con on.

I can cheat and boot them up by unplugging the sensor wire from thermostat housing.

So I assume it is the low speed relay. Is there a way to test this?

Any other suggestions or comments

[VTLS1]

test with a multimeter,if not work just change the relay

[mattcooper]

Unfortunately I dont have a working multimeter around atm. I placed a wire between "30 and 87" and the fans booted up. So would that rule the relay as faulty?

[bhopper]

He there matt yeah go to holden and get a relay ,dont get one from supercheap or anywhere as the pin setup is different from what i have read myn did the same but i had a spare one from a wreck i had and it fixed the problem ,also when you unplug the temp switch and they turn on it dose indicate your wiring is functioning and is all ok ,the low speed should turn on after 6 sec and the high should turn on after 10 sec ,so if its not relay may be temp switch not sending signal to turn them on.

cheers bhopper

[mattcooper]

Cool any idea what the approx rate at holden is for a relay?

[bhopper]

Hey no idea could be anywhere from 12-25 just ring spare parts and while your at it get a price on the temp switch they can be expensive when i got one last christmas i got a temp switch for 75 but they were usually 120 for temp switch just have to get a good sales person i think.

[mattcooper]

OKay I got a new relay.. $12.50

Im confused... My car doesn't over heat. The gauge sits under half way like normal.
The only reason why Im thinking the fans aren't working is that I don't hear them fire up any more. Eg Mcdonalds drive through.

Now I understand the fans come in on at 104c. I sit the car running for 20 mins and nothing.. Got my mates vt and sat it running for 20 mins and his didn't come on either. How do you actually test the temp of the engine to see when it hits 104c?


How long from a cold engine will it take for these fans to come on at there own will?? approx anyways

Grrr I dont no if theres something wrong or not

[Cheap6]

The fan low speed should be on with the A/C (@ < 30km/h) so that would suggest that something is not working right but it may take a while idling to get above 104C in winter temperatures if you are looking at that.

At 100C the coolant temp sensor should have a resistance of 180 Ohms, @ 104C it should be a little below that so if you can find a DMM you might measure that.

If you put a pot/variable resistor across the coolant temp. sensor harness terminals and run the resistance through the just less than 100C/180 Ohms value, the low then high fan speeds should switch on, so you can see if both work not just the high. It would be sensible to use a fixed low value - 10 or 20 Ohm - resistor in series with the pot to avoid even the possibility of a short across the sensor.

[mattcooper]

Hey my air con doesn't work at all so I cant do that test :-(

And I dont have a multimeter to test the ohm's

Grrr Any other ways ?

[moose man]

Your a/c doesn't need to work to test it. Just bridge the terminals on the pressure switch to test the fans. The compressor might turn for a moment, but it shouldn't do any harm for a few seconds.

Also, you can safely short out the coolant temp sender wire to test the fans. There's no need to use a resistor inline.

[bhopper]

Hey matt not shore about shorting them out but as i said if you unplug the connector on the temp switch and they start up the wiring is all fine ive also had to do one of those myn starting to play games like after 30 sec of car starting they would switch on and not turn off ,not turn on at all etc , just before myn went the fans used to switch on after 5 mins of idling but once it shiy itself the fans wouldnt turn on for easy 20- 25 min also have you tried the special features on your dash to see what temps the car is running.

[mattcooper]

Hey whats the special feature again. Cant remember the procedure? Ignition then hold down the buttons?

[tk55]

,also when you unplug the temp switch and they turn on it dose indicate your wiring is functioning and is all ok ,the low speed should turn on after 6 sec and the high should turn on after 10 sec
cheers bhopper

hey matt, like bhopper said, when you unplug the temp switch did you notice the fan turn on at slow speed first before going fast? if not your slow speed isn't working.

[mattcooper]

hey matt, like bhopper said, when you unplug the temp switch did you notice the fan turn on at slow speed first before going fast? if not your slow speed isn't working.

yes it works slow and fast with the themo wire unplugged..

Yeah i wanna test this temp thing out .. Whats the procedure?

[tk55]

at the speed alert module, hold down the mode and up-arrow buttons while turning on the engine. keep holding the buttons until you heard a few beeps and the display changes to show something else. let go the buttons and scroll through the display with the up arrow (or was it the mode button can't quite remember) until it shows the temp.

usually the easiest method to tun on the slow speed is simply to turn on the air-con. but since your air-con doesn't work you have to wait till the temp hit the 104 deg mark. in this winter, you're going to have a hard time getting the engine to that temp. my ex-vt only get pass that temp when in a traffic jam situation. i guess you can ramp the engine while sitting idle for a few minutes and see if it does it.

alternatively use the resistor bridging method to test it, as described previously by others.