Rad fan not coming on

[Courtnova16v]

Hi. I've just changed my coolant temp sensor and now my rad fan isn't coming on, could a faulty coolant temp sensor be causing this? Thanks.

[Royston]

Fan is is controlled by a switch fitted into the radiator, check the wires haven't come off

[paul james]

Disconnect the plug from the coolant sensor switch in the radiator, and bridge the two connections in it with a bit of wire. If the fan comes on, then you can blame the switch in the rad.

[Jedro]

id done all of the above and a ****load more and still had no luck, turns out the fan wasn't getting enough volts from the switch. ended up just putting a manual fan switch into the dash, fused it etc...
:thumb:

[mowgli]

so the fan switch was possibly goosed, and maybe the thermostat

[Courtnova16v]

Thanks everyone for your suggestions, will give them a go tomorrow and report back. Ow and the coolant sensor I changed was the one on the engine not the rad if that helps.

[Jedro]

so the fan switch was possibly goosed, and maybe the thermostat

you on about mine bud?

nahh i replaced the fan switch with a gm on, also temp senor in the thermostat, bridged the wires, obv checked fuses.......... for some reason it was losing volts from the switch to the fan boggles me

[mowgli]

you on about mine bud?

nahh i replaced the fan switch with a gm on, also temp senor in the thermostat, bridged the wires, obv checked fuses.......... for some reason it was losing volts from the switch to the fan boggles me

so the fan motor was possibly tatered, or there was a bad wire/connection.

i was pointing out to the OP that changing a CTS will do nothing to the workings of the cooling fan. only a wiring fault, a faulty switch or thermostat (or on the rarest occasion, the fan itself) will cause the fan to fail to work.

[Courtnova16v]

I disconnected the plug from the coolant sensor switch in the radiator, and bridged the two connections and the fan came on, so I think I'm going to try another coolant sensor in the rad, my next question is, I have a redtop in my car so do need to get a coolant sensor of an Astra or cav or do I get a normal nova sensor?

[mowgli]

the rad fan only should come on in stationary traffic, or at low speeds on a hot day, fit a std nova one.
if you feel it is marginal, and want to have it come on sooner, find out if an early astra diesel one has a lower switching temperature, or possibly fit a manual switch with some 2 core wire & piggy back spade terminals so that the automatic switch still works, but you can control it from the dash too..