4WD activation or not.
What to check next
Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.
Have the four-wheel-drive control system checked during the fault before replacing the switch or actuator. Provide the intermittent warning and lack of indicator response; do not rely on four-wheel drive until operation is verified.
Guidance references and applicability
Source: Original question and visible replies. Owner reports and other participants' experiences are distinguished. Next steps are editorial guidance for obtaining diagnosis or clarifying the reported findings; they are not a verified repair procedure or an independently confirmed component diagnosis.
Discussion summary
4WD activation or not.
A 2000 Chevrolet Tahoe Z71 intermittently failed to engage push-button four-wheel drive, with no engagement indication and a service-4WD warning. The owner reported that it remained in two-wheel drive and sometimes worked normally later.
Reported outcome: The original owner did not report a confirmed diagnosis or completed repair.
Other participants described actuator wiring and a dashboard switch as causes on their own vehicles. Neither was confirmed for the original Tahoe.
