A negative battery cable is under $10, all it requires is a 10 MM open end wrench and about 5 minutes to install :



As to the " shifter control module", he either means the assembly with the actual shift **** on it ( which has NO vacuum connected to it ), or the TCM ( transmission control module ) which also has no vacuum connection and very seldom goes bad.

I would recommend YOU replace the negative battery cable, make sure you wire brush the connection point on the right fender, and then see what you have.

( If that fixes everything, I'll take 20% of the $3000 as a consultation fee ) - only kidding.