I need to tack weld a bracket to the body of my 2007 Toyota 4Runner. I have a Miller 135 MIG AC welder. I'm concerned about damaging sensitive components like the engine computer, and body control modules; I don't want to fry anything. Is it enough to disconnect the battery and body grounds before welding? Thanks!

 

Well.. In theory the current finds the shortest way, so if you put earth close to where you are welding, no problems.

And in real world situation, weve welded with big MMA-welders CMM's that have computers costing as much as your car, a piece, without even ever disconnecting batteries. How lucky do you feel?

 

I always disconnect the battery.

 

Put the welder's ground as close to the work as practical. If you're worried about a component, disconnect it from everything before welding.

 

i have always done the same,disconnect battery and ground as close to what your welding.

 

they make a setup that clamps across the battery terminals and protects electronics and such, i always borrow my neighbours when i weld, i dont think they are expensive.

https://www.autoelec.com.au/projecta...protect-car-tr

 

My neighbour a few buildings away is always welding on heavy equipment vehicles . Also does welding on many other vehicles. He doesn't remove any batteries , just disconnects them and grounds the vehicle .
When he and I were installing my rear sway bar last spring, he welded a couple plates to my lower control arms in the rear and didn't bother disconnecting the battery, however, it would probably be a good idea to just pull the positive bat cable on anything newer as others mentioned.

Eric

 

battery disconnected, and all electrical components within 18 inches should be disconnected and removed/moved back....including wire harness air bags etc...ground is ground, the whole vehicle is charged so...

my buddy burned up a 5k stereo in a brand new Infinty and a few sensors, had no clue til he tried to deliver the car and they couldnt clear the codes..including air bag codes

...disconnected the battery didnt matter..pulled a repair procedure and right in the procedure it said to remove it etc...cars are complicated, things have changed..

and according to I-car also..18-24 inches to be safe...even though since the 80s, it been taught that the mig wave length doesnt affect car electrical components....but ive seen it more than a few times recently...

i saw it with my eyes, it killed the amps and the speakers..when i say new, i mean a 2018..was a bad day for my friend, thats for sure

 

I took Stan 65 Cutlass' advice and after reading a few welding posts I've decide not to "roll the dice" on this. I ordered a surge protector from Amazon, should be at my front door by Thurs. It connects across the the battery and absorbs any spikes or surges induced by the MIG. There is an air bag sensor within 18" of the weld spot, so I will disconnect and remove that device before striking an arc. Thanks for all the advice and suggestions - I love ClassicOldsmobile.
Rodney

 

IMO, and note that I Am Not A Welder But I Can Melt Medal, it's less risky if you're using a method where the work material is grounded (eg gas shielded MIG) vs methods where the material is energized (TIG, flux). Just make sure the clamp is close and has a good clean connection.