I have to build new seat brackets for my front driver seat because the door side was pulled out before I bought the 4Runner and i did not fix it right away so the scrap tin that Toyota has the seat bolted to ripped right out on the other side. I will do a writeup when I am done with this because it seems from the searches it is a common 3rd gen 4Runner problem, so maybe how I fix it will help someone else.
My question is, I know to disconnect the battery but what about all the other electronics in the vehicle? i am just running a small mig welder but any sort of current could mess things electronic up. So is just disconnecting the battery enough?

 

That is all I have ever done. Just make sure the welding clamp for the mig is close to your work not on the other end of the vehicle. Make sure wires, hoses, lines, ect.. are not real close to the weld as they may be damaged by the heat.

 

X2 on a close clamp. If at all possible always put your ground clamp closest to your work. x2 on disconnecting the battery.

 

You will be fine just disconnecting the battery. And as the others said make sure your ground clamp is close to your work so the current doesnt have to pass all over the place to complete a circut.

 

It's a short circuit so disconnecting the battery will be good. Ground directly to what your welding

 

x3 on as close as posible to what your welding

 

and keep your eyes peeled for fire..I about burnt my old 4runner down welding on the floor...caught some stuff underneath on fire..talk about a sh@ty situation!!!