'66 'Cuda gauges not working

[Bmer89]

Hi all, I'm trying to wrap up a mild restoration on a '66 Barracuda and the gauges have me stumped. They used to work ok(temp, gas, and oil pressure), then worked intermittently, then they worked intermittently and no gas gauge at all, and now none work. Every time I pull the dash out to investigate and reinstall, they would briefly work. Now they won't work at all and I'm at a loss. Gas sending unit is putting out a signal, power is getting to the gauges, gauge works when supplied with power, and there are brand new circuit boards. As far as I can trace, everything has a good connection.

Where should I look next? This might have been covered before somewhere but I genuinely don't have the time to read through all the threads. Thanks in advance!

 

[TrailBeast]

Though it may or may not solve your actual problem a dedicated ground to the cluster would be a really good idea if it doesn't already have one.
If it does make sure it's getting a good contact at both ends.

 

[Bmer89]

I did attach a lead from the circuit board ground point to chassis ground and no change. As I read articles, they make mention of the instrument voltage regulator, would a bad regulator cause these problems and how do I test it?

 

[TrailBeast]

I did attach a lead from the circuit board ground point to chassis ground and no change. As I read articles, they make mention of the instrument voltage regulator, would a bad regulator cause these problems and how do I test it?

If I remember correctly the fuel and temp gauges are the only ones that use the regulator.
Also pretty sure in your car the regulator is built into the fuel gauge, where other are mounted on the back of the cluster.
I'll find a pic for you.

Here's a great article on how to get to it and how to convert it to an electronic regulator instead of the on/off mechanical type that you probably have now.
Early Valiant Barracuda Club - Gauge Repair

 

[Bmer89]

The regulator is indeed built into the gas gauge, and I read an article explaining how to bypass it when it goes bad. So I installed an external regulator and also installed dedicated ground wires to each circuit board. I'll try to get the pictures up here. Anyways, everything is working great now!

 

[Bmer89]