Scott,
When you flip the switch, do you hear air pressure exhaust at the rear suspension? If so, your tag is probably working as designed. That era of SMC built coaches did not lift the tag much, they just unloaded the tag. If you drive around an RV park with the tag lifted on uneven ground you will see air under the tires. They did not use tag up alarms, but you should have a yellow light on your dash that says 'Tag" when the tag is lifted.
Gerald