Upgrades on gauges questions

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Del

Del

Papa66Bcuda
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I'm working on a 66 Barracuda fixing some cracks on my dash pad and replacing the factory gauges with aftermarket ones. My questions are I am replacing the amp guage with a volt guage can the same wires be used that were already being used. And also on the fuel guage by replacing it do you need to pull sending unit out to check what ohms it is or do you replace it with a different one that's matched to the guage. Also by changing out all gauges I assume that the printed circuit boards are no longer needed except for lighting on speedometer and economy guage which I can fix by adding into the lights from the other guages. Thanks just wanting to be sure
 
The 2 wires on the amp gauge are hot at all times. Current passes straight through this type gauge. You'll need to connect those 2 wires together to keep everything powered. A volts gauge is different. It gets a switched hot and a ground. There is a switched hot wire to your OEM inst' panel. It will be just black or blue with white tracer. It fed switched 12 volts into your inst' voltage regulator which was probably inside your fuel gauge ( its a 3 post gauge? ). Factory wiring diagrams would help you.
The OEM thermal gauges and senders operate on 80-10 scale so that's the type gauge you'll need when using original sender. Aftermarket fuel gauge will not have a voltage limiter/regulator inside. Aftermarket gauges may operate on 12 volts and not need a limiter/regulator.
How you deal with illumination, need the circuit boards or not?, I don't know.
 
I used the factory sender with my fuel gauge. If memory serves me it's 10-73 ohms auto meter has one listed for Chrysler. The printed board is no longer needed. There should be a wire going to the plug in for the board for dash lights.
I think the wires for the ammeter come off the alternator circuit, and would only show voltage if the alternator is operating. Not 100% sure about that maybe someone else will chime in on that
 
Del said:
I am replacing the amp guage with a volt guage can the same wires be used that were already being used
Click to expand...
No. The ammeter is an internally shunted meter in the battery feed/charging circuit.
See where its located in the diagram?
upload_2018-12-26_8-16-18.png
1960 Imperial and Chrysler Tech - Alternator Service page 8

The other gages operate through a voltage regulator when the ignition switch is in run.
1963 Electrical Diagnosis, Voltage Limiter & Gage Operation, p. 10. Master Technician's Service Conference
 
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There are threads about using stick on led lighting strips to light the dash. Check it out.you wouldn’t need the factory circuit board for the lights this way. You get to pick a color too.
 
RedFish said:
The 2 wires on the amp gauge are hot at all times. Current passes straight through this type gauge. You'll need to connect those 2 wires together to keep everything powered. A volts gauge is different. It gets a switched hot and a ground. There is a switched hot wire to your OEM inst' panel. It will be just black or blue with white tracer. It fed switched 12 volts into your inst' voltage regulator which was probably inside your fuel gauge ( its a 3 post gauge? ). Factory wiring diagrams would help you.
The OEM thermal gauges and senders operate on 80-10 scale so that's the type gauge you'll need when using original sender. Aftermarket fuel gauge will not have a voltage limiter/regulator inside. Aftermarket gauges may operate on 12 volts and not need a limiter/regulator.
How you deal with illumination, need the circuit boards or not?, I don't know.
Click to expand...
Sorry to ask a silly question but if you used a amp guage then could you use the 2 existing wires like it was hooked up from factory. Thanks
 
sport74 said:
I used the factory sender with my fuel gauge. If memory serves me it's 10-73 ohms auto meter has one listed for Chrysler. The printed board is no longer needed. There should be a wire going to the plug in for the board for dash lights.
I think the wires for the ammeter come off the alternator circuit, and would only show voltage if the alternator is operating. Not 100% sure about that maybe someone else will chime in on that
Click to expand...
I will check Autometers guages. Thanks
 
Mike69cuda said:
There are threads about using stick on led lighting strips to light the dash. Check it out.you wouldn’t need the factory circuit board for the lights this way. You get to pick a color too.
Click to expand...
Thanks I will check out the forums on lighting
 
Del said:
Sorry to ask a silly question but if you used a amp guage then could you use the 2 existing wires like it was hooked up from factory. Thanks
Click to expand...
Yes a aftermarket AMP gauge would use the same 2 wires as OEM amp gauge. You still have a gauge that can shut down the whole car though. If I can opt for a VOLTS gauge I will... and did so for that one reason.
 
RedFish said:
Yes a aftermarket AMP gauge would use the same 2 wires as OEM amp gauge
Click to expand...
True. At one time after market, under dash, gage sets often included an internally shunted ammeter.
 
RedFish said:
Yes a aftermarket AMP gauge would use the same 2 wires as OEM amp gauge. You still have a gauge that can shut down the whole car though. If I can opt for a VOLTS gauge I will... and did so for that one reason.
Click to expand...
When you put a volt guage in did you use one of the wires from tha original amp guage. It looks like if you used any switched 12 volt to positive side and other to a ground is all needed. Correct me if I'm wrong please. Thanks
 
Del said:
When you put a volt guage in did you use one of the wires from tha original amp guage. It looks like if you used any switched 12 volt to positive side and other to a ground is all needed. Correct me if I'm wrong please. Thanks
Click to expand...

Tap the switched 12 volts that is already present to inst' panel.
To use the always hot wires to amp gauge creates always on battery drain. This is the difference in amp gauge and volt gauge designs. The amp gauge does not have a direct to ground path on black wire side. A volt gauge does. So volt gauge needs to be on switched on/off and ground ( like a light bulb or most anything else ). You would simply connect the amp gauge red and black together to delete that gauge.
 
RedFish said:
Tap the switched 12 volts that is already present to inst' panel.
To use the always hot wires to amp gauge creates always on battery drain. This is the difference in amp gauge and volt gauge designs. The amp gauge does not have a direct to ground path on black wire side. A volt gauge does. So volt gauge needs to be on switched on/off and ground ( like a light bulb or most anything else ). You would simply connect the amp gauge red and black together to delete that gauge.
Click to expand...
Thank you I sometimes get confused on electrical wiring and need a reminder and need to be reassured what I'm doing. That's what I love about this forum the amount of help and knowledge that's here. Thank you again
 
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