Need help finding new temperature gauge
Yep. Parallel means make them sort of like a ladder. Just lay all 4 side by side, and twist all four wires at one end, then twist all 4 wires at the other, and solder
Testing the IVR is a little tough. You would really have to check the gauges first. "Somewhere" I've got what it takes (for voltage) to directly operate a gauge. I believe it's 2 dry cells should give you full scale on a gauge movement with nothing else tied to it, but not sure
You can also check them "against each other" If they are in the cluster, pull the IVR out, and hook a battery to the two sender connections on the two gauges (temp and fuel) Polarity does not matter. The two gauges should both come up to the same reading.
The problem with trying to test IVR is that the old ones "pulse" like a flasher. The reason you don't see this on the gauges is that the gauges react slowly. The replacement solid state ones may not regulator properly without some load, so trying to test them gets tricky as well
Be careful what you hook up. Running full 12V to the gauges will likely burn them up
Edit. Here we go. These are to show that two gauges agree, meaning that either they are both wrong---and off aby the same amount, or else the fact that they agree tends to show they are still accurate
Check out these two threads
http://www.forabodiesonly.com/mopar/showthread.php?t=207604&highlight=gauges
http://www.forabodiesonly.com/mopar/showthread.php?t=205270&highlight=gauges
The top photo is with both gauges wired in parallel. They are being supplied 3V from a power supply, and you can see they both read close to full scale
The bottom photo is in series, and you can see both show between empty/ cold and the first mark on the scale