Radiator fan not coming on

[TommyP]

Whats the most likely cause for the electric radiator fan not coming on at temperature.
The fan works perfect if its hard wired. so I could wire it up to a dashboard switch and turn it on manually when required, but wold prefer it to work as it should. Is it switched on by a relay and where is it located on a 99 model.
Any advice gratefully received
Cheers

[Incorrigible]

There mnay be a relay but they're usually switched by the otter switch alone (the one tht bolts into the radiator)

3 things it could be...

a. broken otter switch - replace switch
b. air in the radiator - bleed radiator
c. dodgy temperature gauge showing 100 when it's actually only 80

[TommyP]

Cheers Incorrigible, Looks like the otter switch is faulty cos if you bypass that the fan comes on.
The otter switch is new and came with the new radiator, but I suppose that can happen.