Why the service LTPWS light stay on on my 1994 corvette LT-1

You need to reset the low tire pressure fault waring, this can be a defective sensor. Read the procedure below.
Replace sensors as required.
Clear DTCs by grounding DLC (under dash in front of driver) terminal 6 to 5, three times in ten seconds.
Receiver/control module will confirm that its memory has been cleared by illuminating both the "L0W/FLAT TIRE" and "SERVICE LTPWS" lamps at the same time. Both lamps will remain ON until the ignition is turned to the OFF position and then back to "ON".

RF sensor MUST be color code BLUE.
If you still get codes, read out the DTCs by connecting DLC terminal 6 to 5 to flash LTPWS. Look for 23, 33, 43, 53 or 24, 34, 44, 54. Right front is LOW TIRE DTC 53 and WHEEL SENSOR DTC 54.

All codes will be preceded with DTC 12. DTC 99 is possible receiver fault.