We have all had to do repairs or "ADD ONS" that require the use of a welder.
No matter if its a new trailer hitch or a little repair on the exhaust system.
A word of caution here. Any time you weld on a rig with electronics (ECM) you must disconnect the batteries.
Also make sure the ground on the welder is as close as possible to the area being worked on. LIKE REAL CLOSE
Failure to do so can result in severe and in many cases catastrophic damage to the sensitive electronic equipment on board.
The welder can cause voltage to flow into places that should not have voltage.
You never really know just what is going to happen when you lite off the mig welder without unhooking the batteries.
I witnessed a local fellow doing a trailer hitch on a Mercedes a few years back, find that after the hitch was on that the car would no longer run.
The results of his failure to heed the warning was a burned out ECM and several other issues that came haunting.
The cost for the repairs were staggering and far outweighed what he made on the hitch.
Just a good point to remember.
Many class 8 trucks have stickers on the frame that say, "Disconnect batteries before doing any welding"
Cat suggests unplugging the ECM on the engine first.
Best
Robyn