#2 in illustration, With auxiliary heater prep pack (GZBAB) #2 in illustration, With heater/AC prep pack (GZBAC) #2 in illustration, With heater/AC prep pack deluxe (GZBAD)
#2 in illustration - small a/c tube that attaches to the auxiliary evaporator thermostaic expansion valve (TXV), with high output (auxiliary) heater/AC, 3/8" O.D.
A/C low pressure tube asy, with heater/AC prep pack or prep pack deluxe, 3/4" O.D., attaches from under hood 19E558 A/C line assembly to 19752 valve located under LH front door