Unfortunately, the voltage limiter plugs in to the back of the circuit board in the instrument cluster.
I just went through all this with my '68 GTX's gauges, too. I had no temp or gas gauge function, either.
No dash lights to boot.
Wound up taking the cluster out, re-soldering some loose pins on the main connector, replacing the voltage limiter with a digital one I found on ebay (pricy but worth every penny) and replacing all light sockets and bulbs.
Replaced that pricy dimmer switch (you would be amazed what all Mopar ran to THAT switch - they used it for a junction point for a LOT of things you'd never expect) and everything came back to life on the instrument panel after all that.
There's a fella on eBay who rebuilds the dimmer switches and does a fantastic job of it.
Of course, there's also a new sending unit in the gas tank, too....
This car sat in the mud behind a barn for years, so you can imagine the shape the wiring was in. All good now.
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Oh, and if you haven't already - get a factory service manual for the car. The wiring diagrams alone are worth the cost.