Ignition on... Fans on

[WazzaL]

I turn the key in the ignition and immediately both fans spring into life (car is stone cold) and won't turn off until I remove the key again.


I know that this has been done before,
but just for clarity, can someone tell me the likely reasons?

Dodgy Otter Switch...

Any others?

[JonathanT]

I have this but the problem seems to have fixed itself for now...

dodgy fan relays or connections to the relays?
dodgy earth connection?

[Chimjunkie]

The otter switch should work a relay to power the fans. Try disconnecting a lead from the otter switch. If the fans stop (engine cold) then the switch is fooked. If not then the problem is further down the line.

[WazzaL]

Chimjunkie said:

The otter switch should work a relay to power the fans.

Is this the 2 relays (one for each fan) in the fuse box in the footwell.

Or is this another fuse, as suggested in another thread, under the dash...

[spend]

The relay(s) and fuse(s) for the fans will all be in your fusebox. Pulling the otter switch spades off will tell you if the fault is with the otter switch. Pulling the relays and replacing (with a good one) will tell you if a relay has stuck on. Fuses unlikely to be problem as they normally stop things working

Dave

[CLN1]

When I had that problem with the Griff I found that I'd accidently switched the fan override switch which is located on the steering coloum shroud on some cars.

Colin.

[Andy 'P']

WazzaL said:

Is this the 2 relays (one for each fan) in the fuse box in the footwell.

As you have the two relay version I doubt very much if you have a problem with both of them at the same time, therefore I would suspect the otter switch. As otter switch grounds the feed from the relay coils to chassis earth, do as mentioned previously and remove "both" cables from the switch, keep them apart and away from the chassis, then with the ignition on the fans should stop. If not then it looks like the relays are being grounded elsewhere, again as it is both fans I would suspect the feed cable to the otter switch as it is the only common point. Hope this helps.

[spend]

Andy 'P' said:

WazzaL said:

Is this the 2 relays (one for each fan) in the fuse box in the footwell.

As you have the two relay version I doubt very much if you have a problem with both of them at the same time, therefore I would suspect the otter switch. As otter switch grounds the feed from the relay coils to chassis earth, do as mentioned previously and remove "both" cables from the switch, keep them apart and away from the chassis, then with the ignition on the fans should stop. If not then it looks like the relays are being grounded elsewhere, again as it is both fans I would suspect the feed cable to the otter switch as it is the only common point. Hope this helps.

They don't all work like that... Some are wired so that the first relay is switched on by the otter switch, then the 'first fan' switches on the second relay.

Dave

[Andy 'P']

Apologies wasn't aware some are wired that way, thanks for correcting me Dave. WazzaL let us know the outcome,
Cheers
Andy 'P'

[WazzaL]

Frustratingly, everytime I went to check the switch this weekend, the fans would not switch on with the ignition. However, when I had to go out at that point they were running again...

Lends itself to the Switch I suppose. Will have another look this eve when I get home, see if the fault will manifest itself this time.

[nicktowe]

This happenned to me. It was a blown relay that had failed in the on position