EBCM/ Electrical Repair Concern

[JGR2500HD]

Just picked up my 2015 2500HD 6.0L WT from the dealer after taking it in for service stabilitrak, service trailer brake/ ABS being on.  They told me it was the EBCM and ordered a new one. After installing new EBCM, they said it couldnt be programmed. Found a wire with high resistance from fuse block to BCM. So they spliced in a new wire from fuse block to BCM. Then discovered the SRS light was on and it branched off somewhere between the splice. So then they had to splice in a wake signal wire to SIR module.  Then everything worked.  Questioning why they wouldnt replace the wiring harness.  Not sure if splices will have the longevity a new harness would have.  Service advisor said it was caused by salt like it was somehow my fault but they took care of all  the wite splicing internally so I wasnt charged.  Its under extended waranty for about 4k more miles so I would think they would replace the defective wiring harness. If it was caused by salt couldnt other wires in that harness be affected.  Not sure how concerned to be or if I should push for replacement or accept the splice repairs.  I havent looked yet to see what the repair looks like since it was getting dark and snowing but if salt penetrated the factory harness arent the splices going to be more exposed and I would think a proper splice would be soldered and shrink wrapped and taped into the harness.  Will know more about how they did it when i look tomorrow. Looking for opinions or past experiences. Thanks in advance.