Volvo Repair: Volvo trailer wiring, draw tite, volvo dealer

Question
I have purchased a trailer hitch from draw tite which includes a wiring harness. The harness requires that wires be spliced into the stop, turn and tailight wiring. The dealer states that if I cut wires I will void warranty on the electrical system. Dealer does not know how to wire it. Is it possible that a plug in exists on the S60 for a 4 pin connector so that splicing is not required? If splicing is required which wires are spliced as there are numerous wires running from the lights. The wiring kit includes an isolator module.

Answer
if is original volvo trailer harnes you can disconect it from the conector no cuting needed   you can buy volvo trailer harnes from volvo .you say volvo dealer dont know to wire harnes ?if is volvo harnes they know how to do it .best is and cheapest  to install just go to u haul let them install new harnes and the hitch .good luck