If there is a short somewhere in the gage wiring, and I've seen the posts short to the chassis of the cluster, that will crap out the "regulator" fairly quickly. The "regulator" is what they used to call a vibrator, it has a set of contacts that open and close quickly to regulate the voltage down to appox. 5 volts. if you have a partial or complete short to ground, then the contacts will either burn up, or worse, short. If they short, they will put 12 volts direct to the 3 gages and the overcurrent will open the meter movements. I'd check the gage circuit really well if I had just lost 2 or more regulators. You may have a post that is intermittently shorting to the chassis of the cluster. You take the cluster out, the short goes away. Install the new regulator, put it all back together, looks good. Drive down the road, hit a bump, TADA, short is back and the gages stop working. By the time you get home, the short has crapped out the regulator,and the cycle starts again.
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