A quick fan question please

[gateeast]

Fans not working at 100 degs

With the ignition on but not the engine the fans work and if I short the otter switch fans work.

Help.


Also does it matter which way around the otter switch wires go please?

[Wildfire]

Faulty Relay?

[gateeast]

Thank you to both, relay (it's a 4.3) is new.

[EGB]

? Faulty electrical connections on otter perhaps?. Clean and crimp them up to make a tight fit. A wiggle indicates a poor loose fit.

[Loubaruch]

If shorting the otter switch operates the fan then the wiring and relay are OK.

Otter switches are prone to failure, easy to change.

As a backup it is worth having a manual switch on the dash, the panel lights switch on the side of the steering wheel cover is really redundant and ideal as it has a second set of contacts to operate a lamp, there is an unused lamp in the speedo or rev counter (cannot remember which) that can indicate the switch is on.

[gateeast]

Does anyone know what conditions need to be met to make the fans come on please. Is it otter switch only or is there a sensor in the radiator?

With my prior problem - an air lock - the swirl pot was hot with a new otter switch fitted but no fans but the radiator was cold.

Sorry for all the questions.

[steve-V8s]

Fans should run if otter switch activated and ignition is on, there is no other sensor. The thermal switch/ sensor/ otter switch or whatever you want to call it is sometimes in the swirl tank and sometimes on the radiator, although I think that tends to be on later cars. The otter switch powers a relay which runs the fans. On later cars there is a separate relay for each fan with separate wires, early ones have just one relay.

There are separate sensors for the gauge and the ECU but neither of them have anything to do with the fans unless it has been modified.

[spend]

This may be one of the cars that has the otter grounded to one of the alternator terminals, plug the green/pink wire to one side of the otter switch and then run a spade terminal from the other side to a good ground.

[gateeast]

Working !!

EGB spot on, just a poor connection on the otter switch, seemed to be a good fit but obviously not.

Thank you to all.