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Erratic cooling fan

Posted: Sun Feb 10, 2019 10:37 am
by dragonflyjewels
Has anyone else had problems with erratic operation of the cooling fan ? Ours started on the GT some years ago when it was parked at my daughter's house and her hubby arrived home from work and heard the fan on, several hours after we arrived. We have had the switch and thermostat changed several times, but it still occasionally turns on when parked and then stays on. Al has now got in the habit of disconnecting it but doesn't always remember to put it back on so he is threatening to fit a switch on the dashboard. It's one of those annoyingly random faults that never happens at the repair shop - we've tried leaving it with them to use as a run around for a few days but it's never done it there.

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 12:01 pm
by Alan 480
Seems 'odd' that it does it with more than one switch . . . ..
I did have odd effects once , but then it failed completely so is now an after-market switch on the top cooling hose (I had it left over from a previous project)
only used the high speed option.

I fed it from an 'ignition switched' cicuit so that it CANNOT run if you get out of the car, saves battery going flat :wink:

I'm never really sure that it would need to run after ignition switched off as the water in top of block etc might stay hot without water circulation and the switch is on the radiator :?

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 12:59 pm
by dragonflyjewels
I fed it from an 'ignition switched' cicuit so that it CANNOT run if you get out of the car, saves battery going flat :wink:

I'm never really sure that it would need to run after ignition switched off as the water in top of block etc might stay hot without water circulation and the switch is on the radiator :?
Thanks Alan, that sounds a better option than a dashboard switch.

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 5:02 pm
by jifflemon
Does it have a/c? It’s just I thought ac cars have a different cooling circuit so maybe the kids on the ac side of the switching?

If you do decide to do a manual override, put a relay in; rad fans pull a LOT of current!

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 6:32 pm
by dragonflyjewels
Yes, it does have ac, can I have a translation of kids ?

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 7:25 pm
by jifflemon
Doh! Kids?? :rofl:

The cooling fan circuit is a simple switched circuit; I’m wondering (as the major components of it have been changed) if it’s the ac side that’s switching the fans on?

Re: Erratic cooling fan

Posted: Sun Feb 10, 2019 7:35 pm
by WhiteWolf
I know on my turbo in the summer after it has been toed for a bit the cooling fan will stay on after ignition off until the temperature drops to a preset level, it has stayed on for about 15/20 minutes before.. Maybe the sensor that sends the signal for shutoff has had it..

Re: Erratic cooling fan

Posted: Mon Feb 11, 2019 1:03 pm
by dragonflyjewels
Maybe the sensor that sends the signal for shutoff has had it..
Now that sounds entirely logical, I'll talk to the repairman about it.

Thanks for all advice