coolant temp sender

My wifes red auto cabby 1.8 clipper has a fault that the temp guage doesnt work.

The red light flashes when your turn the ignition for a few seconds and goes out as normal but the guage never moves.

I guess the first thing to try is a new temp sender but Im confused which one it is?

The black plastic flange coming off the head with two senders in are what exactly?

Im guessing one is a coolant temp sender and I thought the other would be a rad fan switch but the rad has its own switch so what is what? Im confused?

The fan switch is working as it does kick in and out. Just would be nice if the guage worked so I could keep an eye on the temp.

Please help

Thanks

the coolant temp sensor is the black one in the front or side flange, with a red/yellow wire. the red and grey ones are thermo switches for the autochoke and inlet manifold heaters

Thanks rubjonny!

I will check out the colour or the senders and replace accordingly.

If no change I guess the binnacle is knackered. Will the red light still flash at me if its got too hot or does this only function if the gauge actually moves?

the light is joined to the gauge so it wont work if the gauge isnt, to test the wiring and clocks jump the red/yellow wire to ground and it should go to full

Got a new temp sender on ebay for £8.50.

Now fitted and all working again!

Was a bit fiddly as it was the sender on the underside of the flange.

Thanks for the advice!