65 A Bodie fuel & temp gauge problems

Gauges are not that complicated, follow the path.

The key switch on has TWO power outputs............accessory, and "ignition run." That is, continuous outputs

The start output and the brown IGN2 ballast bypass are only hot in "start."

So all power that dies when off is either from ACC or "run."

So the key feeds switched 12V "ignition run" power to the cluster, and that power runs the oil lamp, gauges, etc. That power feeds to the IVR terminal of the fuel gauge, and do NOT ask me why Mopar just HAD to build it inside the gauge!!!

The regulated gauge power leaves the IVR, and connects to the fuel gauge internally, then also branches off to a terminal on the back of the gauge. This is the IVR output which jumpers over to the oil and temp gauge and powers them.

From this point all three gauges (not the ammeter) work the same. The IVR power feeds to one terminal of each gauge, through the gauge, and out on the respective sender terminals. From there the sender wires go to the senders and to ground. The temp and oil senders go out through the bulkhead connector, and the fuel gauge goes down to the left kick panel, connects to the rear harness, and on back to the tank sender, and as you know, the sender must be grounded due to tank rust etc, and a poor ground between sender/ tank/ and body.

It is just a simple series circuit: key---to IVR---through gauge---out sender wire---to sender--to ground.