Question about fuel gauge wiring.
"The wiring path". from ground--to the tank sender---through the sender---out the wire, which goes up into the trunk, up forward in the left kick panel, and there' s a mating connector there for the rear harness. The tail/ turn/stop/ courtesy lamp wiring, backup lamps, and sender wire is in there.
From the kick panel goes up into the instrument wiring harness and goes to the cluster via the multi pin connector(s) which attaches to the circuit board for the cluster
The board traces convey the sender to one of the studs of the gauge.
The gauge is powered by the (various names) IVR, instrument voltage regulator or limiter
if the temp gauge works the limiter is likely OK
AS MENTIONED do a quick test by grounding the sender wire. if that (key on) does not send the gauge to the high side peg, now you get to troubleshoot.
Reconnect the sender wire. Acces the left kick panel and (using the diagrams) find the sender wire. Check that "to ground". It should read less if tank is full, more towards empty. The sender goes from about 23--to about 73 ohms or so. IF YOU READ in that range, consider the tank ground, wiring, sender, etc, OK to that point
Next I would drop the column and pull the cluster
REMOVE battery ground
Generally if column shift, you must disconnect the shifter, loosen the clamp/ plate on the floor, turn the wheels so the flex coupler will move / angle enough, and remove the trim under the column, and the nuts (and one bolt some years) up under the column Drop the column down in the seat.
Now pull cluster mount screws, and reach up in and undo speedo cable, and at some point the two nut connections for the ammeter.
At that point you should be able to tip the cluster down and out toward you, gently work wiith the wiring to get a bit of slack, and unplug the cluster PC board connector
YOU CAN JIG UP the cluster to power and use resistors to simulate the senders and check the gauges. They both read the same with same sender resistance. You can also check gauge against (accurately) measured fuel sender resistance. AKA if it reads about 1/2 tank for R, then the gauge should read "about that."
Resistances:
Possible troubles:
Bad sender, grounding, connection, bad wire connection at the sender, broken wire in harness, bad connection at the kick panel connector
Bad connection at the cluster PC board connector pin, bad IVR or bad IVR connecitons, bad connections at the gauge studs, or bad gauge
There's an old thread on here about repairng/ soldering the PC board connector pins to the board traces. Also you need to solder jumpers across the board traces to the contact fingers for the IVR. The gauges---loosen /tighten the stud nuts a few times to scrub the board traces clean.
While you are in there I'd clean/ replace the board/ lamp sockets/ lamps etc
First thing you need if you don't have, is go over to MyMopar and download the 2-volume 73 service manual. I believe it's Dodge, not Plymouth
"The wiring path". from ground--to the tank sender---through the sender---out the wire, which goes up into the trunk, up forward in the left kick panel, and there' s a mating connector there for the rear harness. The tail/ turn/stop/ courtesy lamp wiring, backup lamps, and sender wire is in there.
From the kick panel goes up into the instrument wiring harness and goes to the cluster via the multi pin connector(s) which attaches to the circuit board for the cluster
The board traces convey the sender to one of the studs of the gauge.
The gauge is powered by the (various names) IVR, instrument voltage regulator or limiter
if the temp gauge works the limiter is likely OK
AS MENTIONED do a quick test by grounding the sender wire. if that (key on) does not send the gauge to the high side peg, now you get to troubleshoot.
Reconnect the sender wire. Acces the left kick panel and (using the diagrams) find the sender wire. Check that "to ground". It should read less if tank is full, more towards empty. The sender goes from about 23--to about 73 ohms or so. IF YOU READ in that range, consider the tank ground, wiring, sender, etc, OK to that point
Next I would drop the column and pull the cluster
REMOVE battery ground
Generally if column shift, you must disconnect the shifter, loosen the clamp/ plate on the floor, turn the wheels so the flex coupler will move / angle enough, and remove the trim under the column, and the nuts (and one bolt some years) up under the column Drop the column down in the seat.
Now pull cluster mount screws, and reach up in and undo speedo cable, and at some point the two nut connections for the ammeter.
At that point you should be able to tip the cluster down and out toward you, gently work wiith the wiring to get a bit of slack, and unplug the cluster PC board connector
YOU CAN JIG UP the cluster to power and use resistors to simulate the senders and check the gauges. They both read the same with same sender resistance. You can also check gauge against (accurately) measured fuel sender resistance. AKA if it reads about 1/2 tank for R, then the gauge should read "about that."
Resistances:
Possible troubles:
Bad sender, grounding, connection, bad wire connection at the sender, broken wire in harness, bad connection at the kick panel connector
Bad connection at the cluster PC board connector pin, bad IVR or bad IVR connecitons, bad connections at the gauge studs, or bad gauge
There's an old thread on here about repairng/ soldering the PC board connector pins to the board traces. Also you need to solder jumpers across the board traces to the contact fingers for the IVR. The gauges---loosen /tighten the stud nuts a few times to scrub the board traces clean.
While you are in there I'd clean/ replace the board/ lamp sockets/ lamps etc
