Dashboard voltage limiter?

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Mojoe9955

Mojoe9955

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I'm looking at the dashboard voltage limiter and it has a piece cardboard under it. At first I thought it just fell into that position, but upon further investigation i see that it was intentionally put there. Punched specifically through the center pin that goes to the brake warning lamp and the condenser wire that plugs into the same spot. Anyone know why it may have been done?
Also in many attempts to get a fuel gauge working I've swapped that part around from various dashboards I have lying around to no avail, I've read it may be a ground issue. The sending unit is grounded to the body of the tank and on 3 cars the gauges register from time to time, but never seem to be accurate when doing so. Any help with that?
Thanks

20250320_085116.jpg
 
Mojoe9955 said:
Also in many attempts to get a fuel gauge working I've swapped that part around from various dashboards I have lying around to no avail, I've read it may be a ground issue. The sending unit is grounded to the body of the tank and on 3 cars the gauges register from time to time, but never seem to be accurate when doing so. Any help with that?
Click to expand...
The sending unit is grounded to the tank body naturally through the lock ring and tank flange. The problem is when the sending unit/tank assembly is not grounded properly to the car's body or frame. The factory did this by using a ground strap that connected the sending unit's outlet fitting to the metal fuel line, bridging the rubber fuel line connecting the two.
1742479424284.png

Alternately, a ground strap can be run from the tank flange to a convenient spot on the car body or frame.
Failure to do either of these will result in an intermittent or non-working fuel gauge, as there is no proper ground from the tank to the car's chassis due to the insulating pad on top of the tank and the rubber isolating pads between the mounting straps and the tank (even if the pads are not present, the ground is probably not sufficient). Properly ground the sending unit or tank and your "intermittent" issue should go away.
As for the accuracy issue, that could also be related to the ground (or lack thereof) or more likely related to the sender being an aftermarket unit, which are notoriously inaccurate. An NOS unit or good used or refurbed original are usually the two preferred solutions, with a MeterMatch or equivalent box used in conjunction with an aftermarket sender being the other option.
 
New senders, and all manner of grounding techniques. What about a separate ground from the limiter ground pin to the dash frame?
 
If your temp gauge works, the IVR part of the circuit should be OK. So now concentrate on "the path" from there to the sender. Examine the board trace from the IVR to the fuel gauge stud for any breaks, and "ohm" it out IE check for continuity. Loosen/ tighten the gauge nuts about 3 times to 'scrub' the connections. "Rig" the cluster to 12V and ground, and ground the sender wire of the fuel gauge to see if it moves. Watch it and do not ground it longer than necessary to get a reading.

If that works, check the wire from front to rear, and as others have mentioned, concentrate on the fuel sender ground. Devise a way to clamp a ground pigtail to the sender outlet nipple and ground to the body.
 
Mojoe9955 said:
I'm looking at the dashboard voltage limiter and it has a piece cardboard under it. At first I thought it just fell into that position, but upon further investigation i see that it was intentionally put there. Punched specifically through the center pin that goes to the brake warning lamp and the condenser wire that plugs into the same spot. Anyone know why it may have been done
Click to expand...
The fiber board is a insulator to keep the rivets under the IVR from making contact with the traces on the cir board.

The way the IVR works is there is one pin that gets key switched 12v power. It then converts that 12v to pulsed DC at around 5-6 v

Screenshot_20250320-112033.png


Watch this video it will teach you all about our gauges.

 
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Mojoe9955 said:
Also in many attempts to get a fuel gauge working I've swapped that part around from various dashboards I have lying around to no avail, I've read it may be a ground issue. The sending unit is grounded to the body of the tank and on 3 cars the gauges register from time to time, but never seem to be accurate when doing so. Any help with that?
Click to expand...
The cluster MUST be grounded during testing.

The senders ground the gauge pins with varying degrees of resistance more resistance the closer to empty or low temp, the lower the resistance the closer to full or high temp on the gauges.

As 67dart273 noted with the cluster properly powered and grounded you can temporarily short to ground the fuel sender pin and watch for gauge movement

BUT IF YOU SHORT IT FOR TOO LONG YOU WILL BURN OUT THE GAUGE.
 
Good info, Thanks
Is there a ground to the float in the tank?
Are there "idiot light" and mechanical OP and Temp gauges avaliable?
 
Mojoe9955 said:
Is there a ground to the float in the tank?
Click to expand...
The sender gets grounded by a strap that bridges the rubber tube from the sender to the hard line that is attached to the body.

Many times the tank is grounded through the mounting straps.

You can check that with an ohm meter touch clean metal on the tank and on the car body.

Should have low numerical resistance on the order off the same as when you touch the two test leads together.

0 ohms to 1 ohm is probably good.
 
Mojoe9955 said:
Are there "idiot light" and mechanical OP and Temp gauges avaliable
Click to expand...
Not sure what you are asking.

If you are asking if there are aftermarket gauges then yes several options but most will require extensive rewiring to function.
 
Mojoe9955 said:
I'm looking at the dashboard voltage limiter and it has a piece cardboard under it. At first I thought it just fell into that position, but upon further investigation i see that it was intentionally put there. Punched specifically through the center pin that goes to the brake warning lamp and the condenser wire that plugs into the same spot. Anyone know why it may have been done?
Also in many attempts to get a fuel gauge working I've swapped that part around from various dashboards I have lying around to no avail, I've read it may be a ground issue. The sending unit is grounded to the body of the tank and on 3 cars the gauges register from time to time, but never seem to be accurate when doing so. Any help with that?
Thanks

View attachment 1716381541
Click to expand...
My original post, was really about the cardboard between the voltage limiter and circuit board. Anyone seen or done this for any reason?
 
I may have skipped that and went right to the pictures. I didn't see it mentioned or portrayed in the video either. I don't recall seeing it done before on the few gauge clusters I've "worked" on, is this standard practice? Before I put everything back together I want to make sure to do it correctly.
Going back to the sending units for water temp and oil pressure. These never seemed to work as they were not connected or were replaced with aftermarket gauges that have there own senders. I would like to look at the dashboard and see everything working so I guess it is "either, or" unless there is away to have both. Are there combination oil pressure/temperature senders that allow the use of the dash and aftermarket gauges to work together?
 
If you watch eBay etc you can find NOS gauges for a reasonable price.

Realtime engineering RTE limiter - rte makes a great IVR.

Replacement cir boards are available.

I sell a gasket set for 67-71 dart clusters.

The temp sender is easy at the auto parts store.

The tough one is the fuel sender NOS can be had sometimes, rebuildable used are available, aftermarket suck but others have said a "Metermatch" helps.


As for senders that can run two gauges, not likely, the oil pressure can be "T"d, water temp can have alternate sender location so you can have 2 senders. Again fuel will be the tough part.
 
Dana67Dart said:
If you watch eBay etc you can find NOS gauges for a reasonable price.

Realtime engineering RTE limiter - rte makes a great IVR.

Replacement cir boards are available.

I sell a gasket set for 67-71 dart clusters.

The temp sender is easy at the auto parts store.

The tough one is the fuel sender NOS can be had sometimes, rebuildable used are available, aftermarket suck but others have said a "Metermatch" helps.


As for senders that can run two gauges, not likely, the oil pressure can be "T"d, water temp can have alternate sender location so you can have 2 senders. Again fuel will be the tough part.
Click to expand...
Thanks for the help.
 
Dana67Dart said:
The fiber board is a insulator to keep the rivets under the IVR from making contact with the traces on the cir board.

The way the IVR works is there is one pin that gets key switched 12v power. It then converts that 12v to pulsed DC at around 5-6 v

View attachment 1716381621

Watch this video it will teach you all about our gauges.

Click to expand...

Thanks, that was cool and informative. 66 Dart cluster by the way. (or Canadian Valiant) :thumbsup:
 
Interesting regulator that I bought off Amazon. Used it on a non Mopar. You can adjust the voltage to adjust the gauge readings. Dirt cheap

IMG_0066.png
 
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