1988 GMC S15 Jimmy with ST Stamped on Booster; with Brake Code JM3; GM Brake Codes are on the "Service Parts Identification" Sticker; without Master Cylinder;. 1989 GMC S15 Jimmy with ST Stamped on Booster; with Brake Code JM3; GM Brake Codes are on the "Service Parts Identification" Sticker; without Master Cylinder;.
