88 Caravan (submodel: Base, LE, SE) Heater To Pipe; Pipe To Valve; Pipe To Auxiliary Heater Valve. 2004 Silverado 2500 HD (submodel: Base, LS, LT, WT) Heater To Exhaust Gas Recirculation. 2005 Silverado 2500 HD (submodel: Base, LS, LT, WT) Heater Inlet.