Help getting temperature sensor working

Hey guys, trying to get a temperature sensor/gauge working. Here's what I'm working with:

Directly below the spark plug wires you can see where sensor is spliced into the upper radiator hose.

Here's the back side of the gauge.

I have a multimeter: not much of a clue how to use it. (lol)

I tested the wires and it had 12v coming through, and that's as far as I got. I'm not sure how to test what's coming from the sensor?

How is the sensor grounded? Normally the sensor will be in the block or thermostat housing and thus grounded. Try ground the body of the sensor.

yeah, the sensor needs to be in something that's grounded so the gauge can show you how much resistance it's reading in the ground path, with the number that you read on the gauge being a representation of that... i'll assume that the piece that the sender is screwed into is metal... if so, the simple solution for you would be to run a ground wire from that screw next to the sending unit to the engine block with a decent sized wire, which will ground out the body of the sending unit and give the gauge a ground path to give you a temperature reading.

With the sender at that location, you will not get accurate readings until the thermostat opens.

Don49 wrote: How is the sensor grounded? Normally the sensor will be in the block or thermostat housing and thus grounded. Try ground the body of the sensor.

Do you mean run another wire from the sensor (the thing on the radiator hose) to a ground? Or do you mean the gauge isn't grounded correctly? Sorry, I'm really bad with car electronics, I'm working to improve though!

Run another wire from the sensor to a ground. The sensor grounds through the body so if the body is threaded into something that isn't grounded it won't work.

In reply to accordionfolder: Attach the ground wire from the vehicle body, or an engine bolt some where to the metal plate the sensor is screwed into. Maybe the Philips head screw on the plate is for this purpose ( picture 2).

Duh, I just re-read the first comments and it was very clear. I must have been tired.

Thanks, will report back, I'm going to go ahead and get it grounded out today and see if that fixes my woes.

We have ground! But now it's always on since it's wired into something that is always live. I guess I'll tackle that next!

put the power wire to a spare terminal at the fusebox that's labeled "ign" or similar..