Gauges Quit Working After Being Parked

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racingsnake440

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My '63 Dart has been parked up for about 4 years and now the temperature and fuel gauges don't work. They worked when it was parked and the wiring wasn't messed with whilst it was off the road. What's the most likely fix? The oil pressure light and turn signal indicators in the dash flash so it seems like it's getting power.

Thanks
 
Temp and fuel both not working is an indication of the voltage regulator for the gauges not functioning.
On your car I think it is built into the temp gauge.

There are guys on here that repair those if that ends up being the issue.
 
Corrosion at contacts could be why the limiter and gauges stopped. Some of the earlier panels had their limiter housed inside the temp gauge. Any gauge that has 3 contact/mounting posts has a limiter in it.
One of those early panels had a circuit board mounting screw located underneath its plugged in limiter. Factory placed what amounts to a scrap of paper between for insulator. While I am sure that has probably dry rotted and fell away I don't recall which car/panel is which.
Good news is yours is one of the easier panels to remove for service.
 
In one of the gauges is a voltage regulator it is a bimetallic strip with a length of ni-chrome wire wrapped around it. When current runs through the wire it heats up the bimetallic strip causing it to bend and pull apart a contact that removes the current from the wire. This also supplies power to your fuel and temperature gauges and sending units. Most likely the contact has become corroded and is no longer supplying power.
or
one of the terminals or connectors in your dash has corroded and disconnected.

So first thing to try is clean all of the connections on the circuit board. I usually use a pencil eraser to clean the copper.

Check to regulator with an ohm meter, if it is open, very carefully clean the contacts.
or
try to find another gauge
or
you could retro-fit a later model dash regulator into your dash.
 
Search ebay for "voltage limiter" and "Plymouth" (or Dodge) for a <$30 electronic Vreg that works better. Also, the RTE website. Some have photos showing how to disable the Vreg inside your fuel gage. Electronic ones are more reliable and adjustable to help get your fuel or temp gage reading exact. Otherwise, you could try fixing your integral one, but fairly tricky and iffy.
 
Thanks for all the responses. I'll pull the cluster out when I get chance and take a closer look.

Bill, what is the RTE website?
 
So I've pulled the gauges out but can't tell where the voltage limiter is or how to bypass it. Here's a pic.
 

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racingsnake440 said:
So I've pulled the gauges out but can't tell where the voltage limiter is or how to bypass it. Here's a pic.
Click to expand...

The regulator on your car is inside the fuel gauge itself, not on the back of the cluster.
You will have to remove the face from the metal back unit and I think on your car it's these nuts to get the gauge out.
(in any case the nuts right behind the fuel gauge.)

FYI, just bypassing a gauge regulator will fry the gauges.
 

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Here is 'some stuff' on the early cluster

http://www.slantsix.org/articles/instrument-reg/instrument_reg.htm

http://www.chargersourceguide.com/voltagelimiter.html

http://www.forcbodiesonly.com/mopar...ge-limiter-fuel-amp-temp-gauges-66-Sport-Fury

If you google this there is lots of opinions on how to fix them DIY

https://www.google.com/search?newwi...0.6.6.0....0...1c.1.64.img..6.0.0.5bJh8dM22XU

HERE IS THE THING

the electric gauges themselves actually have TWO terminals.......one gets regulated power from the voltage limiter device and the other goes to the sender.

The EARLY cars and the RALLY clusters have the limiter built INSIDE the fuel gauge. In this case, the fuel gage has THREE terminals. Here is the DIFFERENCE between them and the external limiter clusters.

Power comes INTO the third terminal of the fuel gauge. This is switched 12V from the "key." That 12V goes THROUGH the limiter exactly as it would for an external limiter.

That output INTERNALLY feeds power to the fuel gauge AND branches off to one terminal on the "outside" which then feeds REGULATED power to the other gauge or gauges. (Some have oil pressure.)

The THIRD and last fuel gauge terminal goes to the fuel sender.

So in reality the clusters (such as yours) with the fuel gauge internal regulator work exactly the same as the external regulator / limiter. They simply "look" a bit different.

Pay attention to, and read the links. There are different ways to "fix" these. The most popular is to "get into" the fuel gauge and bend the limiter circuit contact over so it's not effective, and or cut the un-needed stuff out of there.

Then wire up an EXTERNAL limiter

The external limiter MUST be grounded. They have three terminals.......12V in, regulated power OUT, and ground
 
The regulator probably creates a contact between one of the two terminals circled in yellow. if it is bad then there will be no voltage on the upper terminal.

One of the 2 terminals circled in red goes to the tank the other +12.

The regulator goes between the +12 and the top terminal circled in yellow.

plug the board back in and use a volt meter to determine what is what.

check to see if there is any voltage on the top terminal if there isn't then your regulator in the fuel gauge is bad. It may just need the contacts cleaned. try that first.

Good luck and be careful it is very easy to burn out the fuel sending unit. maybe you should just disconnect it at the tank to be sure.
 

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gauge has 3 contact posts in a triangle . lower right is 12 volts in. Top center is limited pulse voltage out to temp gauge. The extra piece of copper clipped over that post is a heat sinking shield of sorts. Primitive by todays standards like the mechanical limiter itself, but served the purpose. Lower left is fuel sender signal.
 
So I'm still a little confused:

Looking at the back of the cluster the fuel gauge has three terminals:
I - lower left - 12V ignition switched power
S - lower right - sender unit
A - upper center - 5V limited by reg

The first link that 67Dart273 posted - http://www.slantsix.org/articles/instrument-reg/instrument_reg.htm shows a '67 up style voltage regulator being added (conveniently also to a '63 Dart panel) by connecting terminal I to the input of the limiter and the output to terminal A on the temp gauge (which is also connected to terminal A on the fuel gauge). No mention is made of dismantling the fuel gauge or disabling the original limiter.

Does this work because with the original built in limiter not working there is no connection between I and A on the fuel gauge? Feeding 5V to terminal A on the fuel gauge then allows it to work normally?

What would happen if the original limiter just had dirty contacts and started working again?

Thanks
 
Another website suggests you open the gauge and bend the little thingy. Many have learned the hard way that this doesn't work either.
If you want to know the original limiter cannot cause a problem you will open the gauge and completely amputate that limiter.
No I don't have a BS webpage. I do have real world experience having done exactly as stated above nearly 350 times over a 7 year period. Enough said
 
So, before I go ahead and open the gauge up what tests can I do to confirm the voltage limiter is at fault?

I used an ohm meter and found continuity between all terminals on the fuel gauge. Shouldn't this mean that the voltage limiter is potentially ok?

If I put 12v into terminal I and ground the gauge case I should get 5v at terminal A, correct? And if I then touch terminal S to ground the gauge should move?

If I put 5v into terminal A with the gauge grounded and then touch terminal S to ground, would that also make the gauge move?

Does anyone have any good pics of the inside of the gauge and how to remove the limiter? Is any soldering required to remove it or is it just a case of snipping connections.

Thanks
 
The mechanical limiter inside the fuel gauge will never give you 5 volts out. What is does is pulse 12v on and off. Your regulator can fail in one of 2 ways, either open or shorted. A good regulator will read shorted with an ohm meter, but shorted reading does not mean it is good. If it has failed shorted then you have most likely burned out your fuel sending unit and or your gauge. you can test that with an ohm meter. If it has failed open then your sending unit may be ok. Applying 5 volts across should make the gauge move.
good luck.

Don't apply anything for more than a few seconds to avoid damaging the sending unit or the gauge.
 
I know it seems like I'm the #1 a-hole of a-bodies since I'll tell you what needs to be done but not how to do it.
There really is much more to it than I'm willing to type out here. I'll point out a couple of things... The gauge is extremely fragile. Distort the needle at pivot post and it will loose its ability to travel in a smooth fluid like motion. It'll hang and jump or hang and stay ( most often at switch off / return home ).
Now that the gauge is 50 years old. Fiber board that 3 mounting posts are sweged into will break easier than a saltine cracker.
8 years ago I ruined the first 3 of these instruments I touched. I had purchased 6 before touching the first 1 though so those 3 became spare parts.
I did learn to take them completely apart and restore them but... I also learned that trying to tell every average Joe "how to" would be a wasted effort.
I may not provide these services anymore but I never did offer a spoon full of BS on a webpage in order to sell a part either.
 
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