Cooling fans not working

[dc400]

Hi.my cooling fans have stopped working.I have checked there’s power to connectors at otter switch. Connected a wire to the cable connections to make a circuit I believe the fans should now run but they don’t..Connections at fans is ok. So need new otter switch?. Just checking before I buy a new one. Thanks.

[miniman]

If you short between the otter switch terminals (with the cables connected) the fans should run. If they don’t, it’s something other than the otter switch.

[dc400]

If the power is as far as the otter switch ,if I run wire direct to fans they should work .

[miniman]

If you join those wires together and the fans still don’t run, it’s not the otter switch, it’s something else.

[dc400]

Thanks I will look again tomorrow.

[dc400]

Thanks I will look again tomorrow.

[Belle427]

The connector at the front for them can be a problem area so worth checking it for signs of corrosion.
Relay and fuse checks too.

[mk1fan]

Before spending many £ on new fans run direct 12V to them to see if they work. A 12V tester probe allows you to supply a 12V supply to items. A worthwhile investment (alongside a multimeter) for TVR owner as they are 'cheap'.

[dc400]

Hi. Cooling fans still not working.What I have tried already. Connect fans directly to a battery they work,There is 13.5 volts to wires at otter switch looped the wires together fans still don’t work.All fuses ok. Only thing not checked is relay if this is shot would it stop fans working even if there’s power to cables at otter switch. Don’t know what else to look for. Thanks.

[phillpot]

Yes, think the "Otter switch" just operates the relay.

[mk1fan]

I agree that the otter switch should switch the relay 'on' to energise the load side. You can check the relay easily enough - plenty of youtube tutorials.

You could fit a bridge wire over the relay load side to see if the fans kick in (assuming there is power there). If they do then you know that side of the system works and you can turn your attention to the otter switch side of the system.

[phillpot]

DVR V8 said:

You shouldn't have 13.5 volts at the otter switch. It's a negative that operates the yellow relay top left. If the car is pre 1997 there will be another relay wired into the circuit hanging loose inside the fuse box.

Chimaera could be different but is it not live to relay coil, then onto Otter switch which provides the earth when it "makes"?

[Belle427]

phillpot said:

Chimaera could be different but is it not live to relay coil, then onto Otter switch which provides the earth when it "makes"?

Pretty sure it is.
Can't remember the colours at the otter switch but one will be gound, possibly black in colour.
It's worth checking it is still attached to ground as shorting the otter will do nothing if it isn't.
Relay from memory is a basic 4 pin 30 amp so should be able to get one locally, 40 amp would be better if possible.

Edited by Belle427 on Thursday 29th June 07:30

[dc400]

Thanks. Yes 1wire is black the other is purple . I will get a relay today and give it a try.

[Belle427]

If you remove the purple wire and touch it to a good ground this can test if maybe the otter ground is missing.
Worth a try before buying a relay but useful to have a spare anyway.

[dc400]

All sorted . Changed 2relays and only 1 fan running, changed connectors on other fan both running now . Old connection seemed fine but when I stripped wires back copper wire was black. Trimmed them back put new connections on. Will replace cable when I get over this weekend. Mine is a 96 but this is my fuse board. Thanks everyone for your advice.

[Jasandjules]

I've just had a new radiator fitted, now the fans don't work... Coincidence I wonder.....

[Belle427]

Check the connections to them first, odds on its that.