IVR/Instrument Cluster Voltage Limiter on a 65 Dart

RedFish said
There is no ground fault protection in a basic 7805 regulator. Without chassis ground it will pass full system voltage through the gauges. The solid state regulator package with some level of fault protection built in comes from real time engineering / RTE.
There may a fault somewhere. On positive side it can be at the contact pins of your inst' panels circuit board or the purple wire to fuel sender may be shorted to ground out in the engine bay. I'm really just guessing since you didn't fully describe conditions. Do the needles go home at switch off? Temp needle does but fuel needle at 3/4 at all times?
Proper place to start is buy the good regulator and install it. Add a dedicated ground wire from regulator and metal inst' housing to chassis somewhere.

Hello Redfish. Thank you much for the information. I did add a dedicated ground to the instrument cluster panel frame. With the ignition on, the temp gauge will, within a minute, peg all the way past the farthest right indicator line. The gas gauge will go empty when the ignition is off, but with the ignition on, it goes to 3/4 full. I will check the purple wire for to ground tomorrow to see if there is a short to ground. I did install a new/repop fuel sending unit, but that does not mean it is working properly. Next step, if I can not resolve this, is to install a new voltage limiter.....do you agree? Thanks again. sgrip65