electric parking brake turn on while towing behind Rv did damage to driver side ,had towed it for 340 miles before this happened it is not in my manual to disconnect the ground cable ,when I took it to dealer they gave me a paper stating I need to disconnect the ground cable after putting truck in neutral I told them GM should have put that in the manual instead of tell the dealer .I have turned a claim into GM thru bbb auto line have not heard back yet