If Chevrolet, likely under the dash. But it's not ODBII and does not convey much info. If I recall correctly, on a 95 I had you could jumper a couple pins and the service light would flash indicating a few codes.
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.