64 300 fuel gauge.

[TNT440]

The fuel gauge on my 64 Chrysler is not working. I grounded out the sending unit wire and gauge did not move with ignition switch on. Pulled instrument cluster part way out, checked and confirmed continuity of sending unit wire right up to plug connector at back of cluster. Removed the piece that has the lights and circuit board and confirmed continuity for all of the pins. With ignition switch on I have about 6 volts on 2 of the 3 posts and zero on the third. Temperature gauge is working. I am not sure. How the voltage limiter works or where it is. Any help would be greatly appreciated.

 

[TNT440]

I think the voltage limiter on 64 Chryslers is in the gauge. So I did some testing as per FSM. The cluster is out of the car. There are 3 terminals on back of fuel gauge. With jumper going from positive post on battery to the I terminal, and with jumper going to ground on cluster from negative post. I get a reading as per manual of 12 volts at the I terminal. Manual states that I should be getting a fluctuating reading between 0 and 7 volts at the A and S terminals. I am getting fluctuating readings between 0 and 8 volts at the A terminal which is shared with the temperature gauge. I am getting 0 at the S terminal. The S terminal is connected to the pin that goes to the sending unit. So it looks to me like I need a gauge. I'm posting this because I'm not sure if there is something else I should be looking at, any input would be appreciated. Thanks.

 

[TNT440]

Here is a picture of the back of the fuel gauge

I also don't know what this is. Looks like a condenser

 

[Big_John]

That's a capacitor (condenser) and it's so the voltage limiter doesn't send static to the AM radio.

From reading your post, I agree that it's a bad gauge.

Just for fun, you can attach your meter to the wire from the sending unit and other end to ground and check resistance. If you have an idea of how much gas is in the tank, you can figure if the sender is correct.

10 ohms full, 23 ohms half full and 74 ohms empty. One caveat... I know that is the resistance range for some later cars and I know that 50's cars may use a different range. I'm not sure about 1964, but it will get you close.

 

[TNT440]

That's a capacitor (condenser) and it's so the voltage limiter doesn't send static to the AM radio.

From reading your post, I agree that it's a bad gauge.

Just for fun, you can attach your meter to the wire from the sending unit and other end to ground and check resistance. If you have an idea of how much gas is in the tank, you can figure if the sender is correct.

10 ohms full, 23 ohms half full and 74 ohms empty. One caveat... I know that is the resistance range for some later cars and I know that 50's cars may use a different range. I'm not sure about 1964, but it will get you close.

Thanks. I am not sure how much gas is in the tank as I just bought the car, but I will check and see what kind of reading I get.

 

[HeltaSkelta]

I am neck deep in this same issue, however both my FUEL and TEMP are out, so I'm lead to believe i have an issue with the Voltage Limiter.
I've read the Voltage Limiter is on the back of the Fuel gauge. I'm not convinced we're both talking about the 1964 300(k).

The back of my Fuel Gauge is just 3 posts.
(Junk sacrificial gauge)

The Fuel gauge is installed into the cluster and plugs into the circuit board in the rear (3 posts on left).
This routes power to the gauge, and through the gauge to the temp gauge... somehow.
What i don't see is a Voltage Limiter.
(This is a junkyard cluster for discussion purposes; I'm aware its dirty and likely broken)

I have also been told the Voltage Limiter is inside the Fuel Gauge.
I dismantled a a spare fuel gauge and found that i have no idea what i am looking at.
Is this what limits the voltage? This junk fuel gauge looks burned out regardless...

There is a Voltage Limiter in the Engine Bay located forward of Drivers position, just above the Brake Booster.
I have no idea what this goes to yet. Highly suspect. Likely replace this just for kicks.

*UPDATE: This is the Horn Relay: P/N: 2291436

There is also a Voltage Limiter on the Windshield Wiper just below the Fuel Gauge, but i don't see how this is connected.
No wire or lead goes to/from the same circuit as the Fuel/Temp. This cannot be my issue, unless I've overlooked something.

Does anyone have any better knowledge about this than me? I'm struggling to pin-point this.


TNT440; i have a few spare gauges at this point. What color do you need?

 

[HeltaSkelta]

I dont have all the answers, but the solution that worked for me was to replace the fuel gauge.
If the 'Voltage Limiter' is inside the fuel gauge- its all the same failure to me.

I first tested the existing fuel gauge with a 9v battery.
I connected a negative lead to the FULL side terminal on the back, and a positive lead to the EMPTY side terminal and nothing happened.
The gauge was broken.
I retested with a spare gauge and the needle went to 1/3 tank or thereabouts.
despite the position, the needle moved- meaning it was operable.

I installed the new gauge and I'm pleased to say my whole cluster is now operable.

 

[Big_John]

First thing you need to do is get a Factory Service Manual. Download a copy at Service Manuals – MyMopar Then go to page 6-33 and it will confirm that the voltage regulator is in the fuel gauge.

I have also been told the Voltage Limiter is inside the Fuel Gauge.
I dismantled a a spare fuel gauge and found that i have no idea what i am looking at.
Is this what limits the voltage? This junk fuel gauge looks burned out regardless...

One of those bits with the wire coil wrapped around them is the voltage regulator and one is the fuel gauge. I can't see it well enough, but I believe it's the one on the right.

here is a Voltage Limiter in the Engine Bay located forward of Drivers position, just above the Brake Booster.

That's a horn relay

There is also a Voltage Limiter on the Windshield Wiper just below the Fuel Gauge, but i don't see how this is connected.

That's a circuit breaker.

 

[TNT440]

I am neck deep in this same issue, however both my FUEL and TEMP are out, so I'm lead to believe i have an issue with the Voltage Limiter.
I've read the Voltage Limiter is on the back of the Fuel gauge. I'm not convinced we're both talking about the 1964 300(k).

The back of my Fuel Gauge is just 3 posts.
(Junk sacrificial gauge)
View attachment 735610

The Fuel gauge is installed into the cluster and plugs into the circuit board in the rear (3 posts on left).
This routes power to the gauge, and through the gauge to the temp gauge... somehow.
What i don't see is a Voltage Limiter.
(This is a junkyard cluster for discussion purposes; I'm aware its dirty and likely broken)
View attachment 735611

I have also been told the Voltage Limiter is inside the Fuel Gauge.
I dismantled a a spare fuel gauge and found that i have no idea what i am looking at.
Is this what limits the voltage? This junk fuel gauge looks burned out regardless...
View attachment 735612

There is a Voltage Limiter in the Engine Bay located forward of Drivers position, just above the Brake Booster.
I have no idea what this goes to yet. Highly suspect. Likely replace this just for kicks.
View attachment 735613
*UPDATE: This is the Horn Relay: P/N: 2291436

There is also a Voltage Limiter on the Windshield Wiper just below the Fuel Gauge, but i don't see how this is connected.
No wire or lead goes to/from the same circuit as the Fuel/Temp. This cannot be my issue, unless I've overlooked something.
View attachment 735614

Does anyone have any better knowledge about this than me? I'm struggling to pin-point this.


TNT440; i have a few spare gauges at this point. What color do you need?

Thanks, I picked up an NOS gauge from Hiltop Auto Parts. The gauge is now working.I was suspicious of the almost full reading as I just purchased the car, stuck a dipstick in the tank and it seems to be almost full.

 

[HeltaSkelta]

First thing you need to do is get a Factory Service Manual. Download a copy at Service Manuals – MyMopar Then go to page 6-33 and it will confirm that the voltage regulator is in the fuel gauge.

One of those bits with the wire coil wrapped around them is the voltage regulator and one is the fuel gauge. I can't see it well enough, but I believe it's the one on the right.


That's a horn relay

That's a circuit breaker.

Confirmed- Thanks for the tip, Big_John!
I assumed it had to be the mess of wires within the gauge that i didn't understand based on all the breadcrumbs left for me. I appreciate the verification!

TNT440- Need a wiper knob? =D

 

[TNT440]

Confirmed- Thanks for the tip, Big_John!
I assumed it had to be the mess of wires within the gauge that i didn't understand based on all the breadcrumbs left for me. I appreciate the verification!
View attachment 735676


TNT440- Need a wiper knob? =D

Thanks, no tested the gauge before I installed the know.

 

[TNT440]

Thanks, no tested the gauge before I installed the know.

Knob