Right then, if your gauge is the same as mine wire it as follows.
Gauge Power.
Thick Yellow - Permanent Live 12v,
Thick Purple and Thick Orange - Twist them together and connect to a switched live. (One that becomes live when you switch your lights on.)
Thick Black - A Good Earth.
Sender Power.
Thin Black - A Good Earth. (With the thick black).
Thin Green - To the Red (or sometimes it's white) Wire on your sender.
Thin Red - To a Permanent Live 12v (With the Thick Yellow).
The Sender.
Red (Or White) - To the Thin Green Wire as mentioned above.
Black - I connected mine directly to the battery negative (-).
It's especially important that you connect the thin red to a permanent live, if you connect it to the switched live from your lights it will read slightly lower than normal and the needle will go up and down with your dimmer switch.
Do all of this correctly and the gauge should remember what colour it was when you switched your ignition off (although these Halfords gauges don't always remember no matter how you wire them up) and the temperature needle should still read with the engine/ignition off.
Hope this helps, worked for me but if your car catches fire I cannot be held responsible.
If anyone thinks I've got it wrong please let me know, we don't want any disasters do we?
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