Looking for advice: All gauges move up and down

[XH29N0G]

I started the charger today and noticed a behavior i had not seen before.  I am wondering if anyone can diagnose it and tell me if it is a problem.

The gauges for oil pressure, gas, temperature would rise slowly and then fall slowly and then rise slowly and repeat.  I assume it has to do with the current running through them but do not know where to start diagnosing.

A few years ago i replaced the voltage regulator with an electronic unit.
RTE. I did not do the ammeter to voltage regulator swap. 

Any help will be appreciated.

Thanks

[Dino]

Voltage limiter would have been my first guess, but unlikely with the RTE. My next guess is the pins on the circuit board have poor connections. That was the case with mine. I soldered them onto the board and everything has worked fine since.

[b5blue]

Ignition switch?

[XH29N0G]

Thank you, I will check both of these. 

It will be a week or more before i have an opportunity though

[John_Kunkel]

The factory Instrument Voltage Regulator (IVR) works much like a turn signal flasher only slower, it makes and breaks the current that powers the instruments to achieve a lower voltage. Sounds like yours is working way too slow.