Can't get my dash gauges to work. Car is a 64' B-body Plymouth Sport Fury

Thought it was the voltage regulator, have tested according to the factory manual, and replaced with a NOS one and a NAPA repro with no luck.

Have replaced the gauge cluster with a NOS, no luck. Also tried the various voltage regulators in the new and old dash, no luck.

Have tested both new and old gauges cluster to what the factory manual says, both are working fine!

Have traced all the wiring, from the sensors to the gauges, no broken wires no shorts.

Checked and replaced all he grounds, no luck

What works, Speedo, Amp-meter and ALL the lights, dash lights, indicators etc!

What doesn't work, Fuel gauge, Water temp, clock, Tach and the Horn.

Any suggestions would be greatly appreciated!

 

Well, these old girls just are NOT all that complicated

(One angle I've forgotten I don't remember if these gauges are a "bridge" circuit or not, but all that means is that you need to put a clip lead from the dash cluster to ground on the body to make darn sure

Let's take one thing at a time:

With IGN off, ohmeter from a good ground--to the body, hook the other lead to your temp sender lead wire AT THE GAUGE end.

Now, go around an yank the sender wire off. Make sure the ohmeter shows this. This means, of course, that the sender and it's wire are "good" clear up to the gauge.

You can do the same for the fuel sender, but not to confuse.

Now, take a clip lead (Radioshack?) and ground the sender connection at the gauge to a KNOWN ground at the body. The gauge should read upscale with ignition ON

If not---

could be the gauge itself

could be the instrument regulator, or it may not be getting power.

So--if the gauge will not read.....

With the ignition on, put your voltmeter to body ground, and the pos. lead to the gauge on both terminals.

One terminal should read ZERO--you should have it "clip leaded" to ground.

Put the pos voltmeter on the dash cluster "ground." It should read ZERO, showing the cluster is grounded.

Now put the voltmeter on the "hot" side of the gauge. It should read "some" voltage, and pulsate, showing the panel regulator is working.

If this looks OK, and no gauge reading, Turn off the key, pull both terminals off the gauge, and check across the gauge with your ohmeter. I don't know what the correct reading is, but I'd guess below 1000 ohms somewhere.

 

One thing I have noticed that with the Ampmeter in the dash unhooked, nothing electrical works period, if thats normal it would be a great place to splice in a kill switch!

What I was going to try this weekend was running a ground from the dash to the frame, it could be a grounding issue. Also the block/connector that the wires come thru the firewall at I will clean up and check the connections there, I noted on the wiring diagrams all the effect circuits come thru the same connector.

I'll let you know what happens!

 

NO, you don't want a kill switch in the ammeter circuit. If the car is running, and you open the ammeter, and IF the engine is running fast enough that the alternator is charging, what you have done by opening the ammeter circuit is to leave the charging alternator hooked up the ignition!!!! (This is not a good thing to do, and will cause a surge which can burn up radios and other electronics)

I'm not absolutely sure, but I BELIEVE you indeed need the dash cluster grounded for the gauges. They may be what is known as a "bridge" circuit.

So far as your firewall connector, that is why I suggest you ohm out the sender the way I outlined. I do not believe the fuel gauge sender feeds through the firewall, but rather up through the rear lighting harness which comes up uder the left door sill and up through the left kick panel. There should be a connector there somewhere, and of course, it could be dirty, too.