Is it OK to weld on my car?

I have, in the past always been told that if you need to weld with an electric welder on a car you should remove the cable from the negative battery terminal to protect, primarily the diodes in the alternator. That was many years ago and the electrical systems in cars are much more complicated and sensitive, not to mention expensive. Can I safely use a mig welder on the body of my car if I unhook the battery? Would it help if I removed both battery cables? Thanks.

Removing the ground cable from the battery and insuring that your MIG ground strap is close to your work area you will be fine

Some will go as far as to unplug the harness to the ECU before welding on the car


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I've welded on my mk4 with the battery still hooked up
I've killed a durango with the negative unhooked

to be real safe unhook the negative cable and plop it onto the positive cable to make sure stuff stays well grounded by all possible avenues

i welded on my mk6 tdi with no ill affects. just ground close to what your welding.

Thanks. I thought I was probably OK but I just wanted to be sure.

I welded on my mk6 and yeah ground as close as possible. No problems for me. Good luck.

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My son had welding done to the exhaust pipe down from the flex joint on his 2000 Jetta TDI last week without disconnecting anything ...... car starts and runs fine!

as long as the grounds are disconected on the harness and the battery AND you UNPLUG the ECU, yes you should be fine

I welded on a Mk4 without unhooking anything. Car started and drove fine, and now it can even follow voice commands!


(no it can't, but everything else is just as it was)