I am trying to figure out my gas gauge. Someone cut the wires and I would really like to know how much I have in the tank

The two wires that are on the posts of the gauge are hanging there but where in the world do they go??? I can't find any loose wires under the dash that match up with the wire colors!

Anyone have any ideas? The wire schematic doesn't go into a whole lot of behind the dash detail (or I just can't read it )

_________________
Chris'
Autobody
Restoration
Service

Wow, did I leave out some important info!

It's a '68 Dart.

I did find a blue wire that has been cut coming out of the rear harness. According to the diagram, that is the fuel sending unit wire. What I don't understand is that both of the wires on the gauge posts are red w/blue stripe

All I need is that blue wire to the gauge and the other gauge wire to 12V correct???

_________________
Chris'
Autobody
Restoration
Service

CARS: NO!!! Not 12 volts!

I'm quoting from the 1967 Factory manual, should be the same for your 68 in this case.

Fuel Gage is connected to the sending unit by a dark blue wire that is listed as "G4", part of a five wire connector that plugs into the rear of the gage cluster left of the steering wheel. The Fuel & Temperature gages are supplied by reduced voltage, 5 volts, from the "External Voltage Limiter"; a little metal dome with three legs that plugs into gage cluster circuit board. Don't put 12 volts to these gages unless you like them fried.

From that five way plug-in connector on the circuit board, the dark blue wire snakes its way over to the drivers side kick panel where it enters a six way connector near the floor that mates to the rear wire harness via the door sill to rear wheel well, and over to a hole just behind the rear differential, and to the sending unit in the tank. That dark blue wire could be compromised anywhere between the dash & tank, in other words grounded out or cut.

Dose your temperature gage work? If so, the voltage limiter is doing its job, and your gas gage should work when it is connected to the tank's sending unit.

If you connect the dark blue wire to the gage cluster, and the gage reads full, and you know that the tank is not full, that wire is grounded out somewhere between the gage & sending unit.

If the gage dose not work, look for:
1. Bad voltage limiter.
2. Burned or damaged printed circuit board. ( will need to lower steering wheel, disconnect Speedo, and remove gage cluster to repair)
3. Cut, melted, disconnected wire, or bad multi wire connector.
4. Sending unit not grounded. Check for ground strap between sending unit out-let & metal fuel line that bridges the rubber coupling.
5. Float may not be floating because of a hole in it, in other words water logged & sunk.
6. Sending unit could be bad.
7. Gage could be fried.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks for the reply. I'm not seeing any of what you are describing

I just looked through my "Dart Box" of the used parts replaced/removed and don't see any wires that match up with what is missing
A couple years ago I cleaned up some hacked in gauges and radio components and ever since the gauge is in-op. I just assumed that I removed a ground wire by mistake or cut a wrong wire (something easy to fix). Even at that time I looked at what I removed and couldn't find the connection between what I did and what happened. It was all speaker wire and other odds and ends (really neat under dash light with individual switches .) Nothing with a blue wire or the red w/blue stripes that are on the gauge posts.

I guess it's back under the dash till I have a revelation! I just can't figure out what is missing or why it's missing

_________________
Chris'
Autobody
Restoration
Service

The wiring diagram shows what looks like an internal voltage regulator to me for 68 and 67. Maybe they didn’t bother to draw it all in or maybe it’s wired like it says. I don’t know...

You could maybe try to match it up with the 68 Fury diagram. It shows the external regulator.

You can find a picture of the regulator HERE if you need to see what you’re looking for.

Danny

CARS,
We will get you through this. I don't know level of automotive electrical ability, so I'm starting as if you were a beginner. Please don't take offence, someone else out there in slant land will glean something from this... I hope.

Dash & rear harness diagram here, and engine compartment here.

Scope: To determine if the sending unit, related wire & connectors, and circuit board are in working order.

Wire Diagram Reading:

Look on at dash page about one third down in line with the "8" in 1968; there is a vertical rectangular box with five dots in it. The second dot from the top labeled "DK BLUE" this is the gas gage wire, and that box is the five way connector that plugs into the rear of your instrument cluster circuit board behind the gas & temperature gage. That DK BLUE wire snakes down behind the drivers side kick panel to an eight way connector near the floor to: section #2. Now jump to the left on the diagram to a mirror image eight way connector starting at "section 2" of that box, and trace the "DK BLUE" wire back to the tank's sending unit labeled: "gas gage (Tank Unit)" This is how the wires in your car will be routed, and found.

Actual digging around, locating, identifying, and testing of wires & connections in the car:

Pull your kick panel and locate that DK BLUE wire. Keep in mind that forty years of road mung may have changed its color a wee bit, and a little dish sope & water may bring back its color. Once you find that wire trace it to the gage cluster connector, check for continuity in that short section. Now check from that "#2" section of the rear harness to the sending unit for continuity. Check the sending unit resistance by touching one VOM (volt ohm meter) probe to the threaded electrical connection at the sending unit, and the other to a good ground with your VOM set on 0-100 ohm scale. It should read around 73 ohms empty tank & 10 ohms full if all is good.

Check for a metal ground strap located at the sending unit outlet that jumps the rubber coupling attaching the fuel line to the tank. If the strap is missing or not conducting to ground replace it, or jump it with a length of #14 or 16 wire. The sending unit has to be grounded for the gage to work. A second test is to pull off the wire at the sending unit, ground that wire to the frame with a jumper wire, and have a friend see if the gage moves with the key on. This eliminates the sending unit, and tests the gage. If the Gage moves you have a ground problem (most probable) at the tank, or a bad sending unit.

If the gage is still not working after correcting grounds, bad wire, and poor connections, now the PITA part of this project starts: removing the gage cluster.

Lower or drop your steering wheel by removing three or four bolts under the dash that hold it, and loosening the three or four bolts that hold the column to the floor / firewall. You may have to disconnect the wire harness from the directional signal pig tail (10 wires that come out if the column under the dash), to do this, be gentle that connector can be brittle. Disconnect the speedometer cable from the cluster. Remove the gage cluster from the dash held in place by several Phillips head screws around its perimeter, and the two plug in connectors attached to it.

Inspect the circuit board for melting, delaminating, missing nuts, broken off pins & general condition, and report back what you find. This would be a good time to clean the dash light sockets, their contacts, and replace any bad bulbs.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

See



It's all hacked out!

All I have is the blue wire from the sending unit (not in pic) and the 2 wires in/out of the fuel gauge (both red w/blue stripe).

Someone hacked in a different temp gauge before me and must have removed all the stuff.

As I said, it did work before I removed speaker wire and a few extra toggle switches. Maybe I did remove a external regulator by mistake. Funny thing is I never throw stuff like that away when I do projects like this (in case I need to piece it back together )


So I either need to get a cluster and harness or "temporarily" add a external regulator like in the article. Or plan C, get a custom cluster from Sick 6 and be done with the whole thing


Well, enough of working on my own car. I need to get a truck painted.
Thanks ALOT for all the help. If anyone has suggestions on how they would deal with this situation please pass them on!

_________________
Chris'
Autobody
Restoration
Service

Update: This whole post maybe bupkus. See my next post reguarding this subject.


Hummm....

Looks like a bit of a redesign between '67 & '68 on the gage cluster where the external voltage limiter is missing: see my '67 below. I'm wondering if a later cluster has been swapped into you car, as this same configuration was used on several models & years. I question this because the diagram dose not match up with your cluster. Also there is no circuit board on your cluster. Perhaps someone could elaborate on this.

What dose the white tag say straddling the two gas gage terminals? Internal voltage limiter integral with gage?

Reddish wire closest to speedo should connect to 12 supply if gage has an internal limiter, and the other to the dk blue wire from sending unit. Your unit dose not appear to have external voltage limiter provisions. See photo of 67 cluster below: adjacent to speedo housing there is a cylindrical capacitor and to the right of that three slots where the limiter plugs in to the circuit board.

I can't see what is going on with your temperature gage, but that should connect to a violet wire from water temperature sensing unit in head to the center section of the bulkhead connector terminal "R" on diagram: B, "engine compartment", and a 5 V feed from the limiter.

That five way connector shown on diagram A, "dash", third wire down is black, and feeds the voltage limiter from the fuse block, which after stepped down to 5V by the limiter feeds both gas & temperature gages. You will have to dig around under the dash to find the mates to these clipped leads from the gage cluster. There may be a five way connector up under there that someone spliced into.

Take your diagram and trace out each wire one at a time from the sending unit, temperature sending unit, 12 V feed from fuse block, ground leg for lights etc. and label them with a bit of masking tape, as you go this will become clear to you. Then make the necessary splices to re connect all that mess up. Take your time, be methodical, double check everything, and make sure the battery is disconnected while doing this work. REMEMBER the AMP gage is wired HOT to the battery. If you ground one of those big red wires out you will have a smoky melt down.



I had to make up a small harness to jump out several burnt off pins that the five way connector plugged on to (uper right where orange wire terminates). The yellow wire is substituted for the purple from temperature sending unit. I labeled the termination points on the circuit board B, Y, G, O; for blue, yellow, green orange etc. so I wouldn't screw it up during reassembly. The black feed wire is soldered to the center leg of the voltage limiter. The right slot or leg feeds 5V to both the gas & temperature gages via circuit board.

Dash Lights feed by 12 V via orange wires from rheostat on headlight switch, and to ground by black wire, and need to be in parallel.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

CARS,

I have been looking, thinking, and comparing your gage cluster to mine. I think someone has removed the right side circuit board, hacked a great gaping hole in the pot metal casting to mount an after market or different temperature gage. By doing this they must have scrapped the voltage limiter, most likely fried the gas gage with a 12 V feed.

You may need to locate a right side circuit board, the five pin female side of the connector, a new temperature gage & gas gage, voltage limiter & condenser to repair this unit correctly. Probably a whole cluster will be easer to find.

PM MiDi, I saw shelves full of clusters at his new place of employment in his latest post on social corner, perhaps he can get you one.

Oh, I see just what you need in one of these photos.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks for the reply's WJAJR!!!

I am just going to rig up a external regulator/limiter and get the dash lights to work for now. Till I can find a different cluster and harness.

Thanks for posting the picture! I really didn't know what was missing

_________________
Chris'
Autobody
Restoration
Service

Tonight thanks to everyone's help I reached up under the dash of a '71 Swinger and pulled out a regulator!!!!

Thanks for the pics and article. Without the visualization there is no way I would have known what I was missing and needed.

_________________
Chris'
Autobody
Restoration
Service

Just to follow up. I added the voltage limiter/regulator as per the article that 65Dodge100 posted and all the wiring/cluster info that wjajr provided and I have a functional fuel gauge!!!!
Thanks guys!!!

_________________
Chris'
Autobody
Restoration
Service

Good show old bean! Glad to help.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

HI GUYS, FIRST TIME ON THIS SITE. I WAS READING YOUR INFORMATION BECAUSE I HAVE A 68 DART SLANT SIX, AND IT'S TEMPERATURE GAUGE AND FUEL GAUAGE DON'T WORK AT ALL. I CHANGED THE VOLTAGE LIMITER, AND STILL NOTHING. BOTH SENDING UNITS ARE WORKING FINE, SO I'M AT A BIT OF A LOSS. I CHAECKED THE CURRENT IN THE BOARD, AND I FOUND THAT THERE IS A CURRENT REACHING THE FUEL GAUGE (THE LIGHT ON MY CIRCUIT TESTER BLINKS WHEN IT IS TOUCHED TO THE BOLTS AT THE BACK OF THE FUEL GAUGE). THE LIGHT DOESN'T BLINK AT ALL WHEN TOUCHED TO THE BOLTS AT THE BACK OF THE TEMPERATURE GAUGE. DOES THIS TELL YOU ANYTHING?

THANKS!