I'm new to the Club, so bear with me. Have a '74 2.0. Console temp gauge does not work. Other gauges are fine.
Can someone walk me through the steps to determine if the problem is the wiring, the sender, or the gauge itself??
Any help appreciated.

the gauge operates on a voltage signal. 12V is connected to the gauge then the wire runs to a temp sensor in the bottom of the engine. the temp sensor changes resistance with temperature, changing the voltage to the gauge changing the reading on the gauge.

you can test the gauge but applying a very, very, very small voltage to the gauge (milli or microvolt range to start, too much V will break the gauge) to see if the needle deflects.

you will have the gauge removed to do this test so at the same time, test the continuity of the wire to the temp sensor by disconnecting the wire from the gauge and put a small voltage signal to the wire (a 1.5V AAA battery in a holder with terminals allows you to clip connections, + of battery to wire, - of battery to ground) then disconnect the wire at the temp sensor (under the engine) and see if you have 1.5V to ground using a VOM (volt ohm meter aka multimeter)

there are ALOT of variations of the above procedure.

to test the temp sensor, since it is a thermoresistor (resistance varies with temperature) put it in various temp liquids and measure resistance (VOM useful here too)

The temp gauge is more of a current gauge than voltage. The sender does not put out a voltage on its own and relies on the gauge to 'bias' it with a current. You can test the gauge for full-scale deflection by connecting the terminal to the sender to ground (with ignition on). Assuming there's normal 12V on the gauge, if the meter goes full scale by shorting the sender terminal to ground at the back of the gauge then your meter is good and the problem is in the sender or the wiring harness. If it works shorting it at the sender than the problem is with the sender itself.

Go to the ECU side of the engine compartment......look under the ECU (about where the throttle cable comes out of the engine tin)....If you're lucky, you can spot a brown wire coming up thru the tin just about where the throttle cable comes thru. This is the sender lead. It should be connected to the main harness...if it's not connected to anything...guage no workee.

They do come loose

If you don't have a wire, you gotta look at the driver's side of the engine underneath to see if a wire is connected to the sender.

Have fun..............

Thanks for the good directions to get me started on this. I appreciate the time and info.