Snouldn't be a problem as long as you don't do something silly such as grounding at the 12V battery for a weld done at the rear of the car or grounding through any part of the wiring harness. Current flows between the ground attachment point and the work so obviously you want to keep that distance as short as practical. Automotive electronics are pretty tough in the EMC sense.
I do weld on trucks and cars, it is my practice to disconnect the battery to remove any potential voltage to delicate circuits ECM, controllers ect. Also place ground cable from welder as close as possible to work and electrode, of course if gas welding is used no concerns of stray voltage but just heat. I remember helping my dad with a welding project and was doing some metal lay out work about 30 feet away from my dad when he was welding and I got a shock from touching then pipes I guess I was part of the path of least resistance.Is anyone familiar enough with welding stainless to know if it's potentially possible without messing up the electronics and battery systems? I was just thinking about welding an antenna mount to the body, or ways to mount a rack or other things.
