I've noticed my temperature gauge never rising above the C mark (it used to but very slowly).

I decided to check the sensor and noticed part of the wire directly next to the connector is exposed, from what I can see it doesn't seem to be cut, just exposed

I've got a multimeter but I've never really used it before, how would I go about checking this wire to see if it's any good?

 

you would have to ohm the wire out from the coolant temp sensor back to the ecu to see if its broken or has to much resistance and that can be coming from the fact that the wire is open

 

Unplug the 1-wire sending unit and ground the wire to the engine.

Turn the key to ON(II). Does the temp gauge needle rise toward hot?

 

Would I need these:https://i.imgur.com/Wq3Xi.jpg to do that? If so I'll have to go buy some tomorrow.

 

No, just ground out the wire by touching it to bare metal on the car

 

Just a piece of wire would do, but those might help.

 

Now do I connect the clips/wire to the bare wire thats exposed or do I stick something in the actual boot connector?

 

Sorry to double post but I just tested it and the needle did infact rise, so the wiring is good.

 

Replace the sending unit.