Ok I have read most of the fuel gauge posts and the article on the voltage regulator. I got the cluster removed from my 1965 Valiant and low and behold it had what looked like the newer 67 or later regulator neatly plugged into the back of the cluster. It is part of the assembly and not a really clean patch job. Does this indicate that the cluster was replaced with a 67 or later cluster? How would I tell them apart or ID what year the one I have is from since I don't have anything to compare it to. Also if the temp gauge seems to be working would that mean the the voltage reulator is ok? If the regulator is ok, how do I test the gauge and the sending unit? Thank you for your help.

If you can't tell whether they've changed the guage then it probably doesn't matter if it's different. I've switched my guage three times with different years(did no bad patch jobs.... I'm to good for that ). If the temp guage works the voltage regulator should work. That also means the gas guage has a good ground. Have you checked to see if your gas guage is getting power. Wait a sec, was it the power they shared. Either way since the temp guage works they both either have ground or power, can't remember which. Therefore, you should check whichever one they don't share, it's possible they could be missing that.

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My car may be slow to sixty, but at least it's been reliably slow to sixty for more than thirty years.

Your sender or the wire leading to it is faulty.

Gauges and indicator lamps are fed 12V constantly, and the remote switching device or resistor is mounted in series with the negative or ground side. Why?

In order for your fuel sender to control the positive side of your gauge, it would require 12V from the keyswitch to be fed to it, and another wire from the resistor would have to be run from the sender to your gauge. Also, if either wire were to crack or rub on the frame, it would create a short and either blow a fuse or overheat the resistor. By controlling the ground side of the gauge with the sender you eliminate one wire by just completing the circuit to the gas tank itself, and if the sender wire rubs through to the frame you still have a load in the circuit to regulate current running through it, load being the gauge. So instead of a blown fuse and roasted wiring you have a pegged gauge.

My money's on the sender wire being rusted off of your fuel tank sender. On my Dart the sender sits not on top of the tank but on the front of it, where it can be inspected and repaired easily. Hopefully yours is the same. Just duck under the rear end and have a look.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

It looks like it is a short near the dash on the ground side of the curcuit. I had the cluster out but had plugged all of the wires back in. Then I took my meter and touched the red probe to the power side of the fuel gauge and it did a nice little bounce at 5 volts or so just like it should. Then I pulled the probe and wire out of the meter and touched one end to the sender side of the fuel gauge and the other to the solid steel dash to ground it out. Up popped the fuel gauge to full. By grounding and ungrounding it I could control what level the fuel gauge would show. Conclusion; Everything on the power side of the fuel gauge is working fine. I put the cluster most of the way back in and it showed a quarter tank. I pushed it back into the dash and put the screws back in and when I turned her back on the tank showed empty. Since I had her back together I took her out for a spin and topped off the tank. It only took 4 bucks so the tank is full. Went back home and jacked her up and got a look at the conection at the sending unit and it looked clean and tight. At this point I ran out of day light and had to quit. Tomorrow I will use the meter on the wire at the sending unit and see if I get the 5 volt bounce. If not I will have to remove the cluster AGAIN and see if I can find the short.
To be continued.

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1965 Valiant 200 Convertible 225 ci.
Vista is in Northern San Diego County.

BTW, all my 65's and 66's have had plug in regs, so nothing strange there...

I Based my info on the article "Early A-body Instrument Gauge Problems by Chuck Rivers (10/27/01)" on this website. It states that the unit was made a plug-in in 1967. This is the only one I have taken apart so I don't have a large enough sample to say when it happened. By the way for nooB's like me IVR is the Instrument Voltage Regulator. I would guess that quite a few of the cars out there that were made with the IVR built in have had the cluster updated to the removable type. I mean after 35+ years allot of them are bound to have failed. So the question is When did they swap it in production?

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1965 Valiant 200 Convertible 225 ci.
Vista is in Northern San Diego County.

There is another article here about IVR locations that verifys 65 Valiants were external, along with 66 except Cuda. Apparently, their introduction was staggered for some reason.

For some unknown reason, the Valiant came out with the removable regulator before the Dart. My dad has a '65 Dart and the regulator is in the gauge, as is my '64 Dart. Aparently, the Valiant started using the removable in '65. I haven't checked a '66 Dart, so someone has to tell me if it was internal or external.

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Chuck Rivers, Webmaster