Welding Peterbilt Y pipe

[Nerv]

The Y pipe on the DEF side of my 2014 peterbilt 388 has cracked right in the centre, instead of replacing it $$$$, i have it setup to weld as its cracked perfectly in the Y center. Ive heard so many different procedures on welding on trucks, now im wondering what the best protection is for the ECM and electrical components is. #1. Disconnect negative battery cable. Or #2 hook up surge protector to positive and negative on battery? I have the ground for the welder setup maybe 7 inches or so from the crack on one of the exhaust clamp bolts. What do you guys think?