OER Parts offers a wide selection of Battery Parts & Hardware for your 1988 GMC S15. OER Parts offers 1988 GMC S15 Battery Trays, 1988 GMC S15 Battery Hold Down J-Bolts, 1988 GMC S15 Battery Tray Hold-Down Clamp, 1988 GMC S15 Top Battery Tray Clamp, 1988 GMC S15 Battery Tray Brace, 1988 GMC S15 Quick Release Battery Cable Bolts, 1988 GMC S15 Side Terminal Battery Cable Bolts, 1988 GMC S15 Side Terminal Battery Charging Post, and 1988 GMC S15 Side Post Battery Cable Terminal.