1995 Chevy Tahoe Check gages light comes on

How long since a tune-up? If your fully OBD1 compliant you can check for mil codes. Use a jumper wire between the a and b terminals at the datalink connector, turn key just till dash lites come on, no further, the mil starts flashing, you count the flashes to get the codes. Your looking for two digit codes. The picture is just to show location of A and B terminals, note 12 pin cavity.