Bl**dy fans always on AGAIN

[donatien]

A recurring problem for me. The fans on my Griff now come on from cold with ignition on. Has happened in the past then gone away. No-one seems to be able to find out why.

Otter switch is fine (open circuit when tested at cold) so is it a relay / wiring problem? Mine has twin fans, twin relays.

Also thought it might be damp but it has happened before during summer.

Not a real issue but it means slower to come to temp and more battery drain - hence the odd chance one cold morning it's a non starter.

[david beer]

It would have to be a wiring problem. The coloured wire on the otter is going to earth somewhere between the otter and the fuse box. It would be a job to find it. Probably easier to run a new wire and modify a relay so it doesnt use the original wire, then connect direct to the relay. It will not cause any reliability issues as the relays would still plug into the fuse box. But i guess one should really trace it properly ?

[GreenV8S]

My first guess would be a sticking relay, alternatively a fault in the wiring loom as David said. If you can get at it when the fault happens, measure the voltage on the 12v terminal on the otter switch. If it has 12v on it, its almost certainly a sticking relay. If it has 0V, disconnect the earth. If it goes up to 12v (in which case the fans should stop) its a faulty otter switch. If it stays at 0v it's a wiring fault between the relay holder and the otter switch.

[shpub]

If it is a sticky relay.... only one fan will come on as there is one relay per fan. Obvious culprit is the otter switch. Chcek for continuity between the two contact when the fault occurs. If this is OK... chce the cabling. If that is OK..... might well be an earthing problem as this can do all sorts of funny things....

[donatien]

Cheers guys. It isn't the otter as that is open circuit when tested across the spades and if I pull the otter connections off with ignition on, the fans are still on so the problem is upstream of that.

Regarding the relays - I seem to remember Steve Howard telling me that one feeds the other so they do not both actuate at once. So if the primary got stuck both fans would be on, if the secondary only one. Hence is changing them over worthwhile to isolate the fault? Or am I talking crap again?

Ta

Dave

[david beer]

With the normal set up,it could not be a sticking relay as the fan or fans,would be on even without the ignition on as the power is there all the time, its just the coil side that is ignition switched. If your fans are staggered, someone has done a MOD. As Steve says, a tricky earth can cause allsorts but normally there is something else playing up as it is feeding your symptom. If you are standard set up, i say its that wire shorting down somewhere. Sounds like you have got a fun weekend !