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Old 10-01-2017, 07:49 PM
Fast Orange Fast Orange is offline
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Default Precautions For Welding On Newer Trucks ?

I'm getting ready to do some repairs on a couple rack body trucks. I'm going to be doing quite a bit of AC stick welding on them,and I'm wondering what precautions to take to avoid damaging the electronics.
I've heard everything from doing nothing, to completely disconnecting the batteries, to removing the control modules completely from the truck.
What do you do, if anything?
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Old 10-01-2017, 08:16 PM
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It's not something I regularly do, but doing a search a few months back on the same subject I mostly found tidbits on welding sites with posts from 10 to 18 years old.

I've been told by some 'body mechanics' dent pounder types that speak of removing connections at the controllers/ECU etc, but also added that there are times it's all but impossible to get to without spending lots of time tearing stuff apart.

A good friend needed some repairs done to his old rack on the back of his new truck, 2017, after I mentioned about disconnecting a few things I also mentioned he would agree should something go south he was pre-warned. He removed hot and grnd to batteries and gave up on the ECU after looking at it's connections.

I just kept the ground right at and close to the area's that needed welding. Did the same thing while using the plasma.

I think he was more concerned with keeping the paint protected than anything else. Old tarps wet with the hose took care of that.
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Old 10-02-2017, 05:41 AM
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It's not rocket surgery.

Unhook the batteries and keep the ground and work lead as close as possible. No issues yet for me.
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Old 10-02-2017, 11:46 AM
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Quote:
Originally Posted by SmokinDodge View Post
It's not rocket surgery.

Unhook the batteries and keep the ground and work lead as close as possible. No issues yet for me.
What he said

Electrical current from welding (and most electrical current for that matter) travels the path of least resistance. also, when welding to frame or body, the chassis of a vehicle is considered to be grounded to the negative terminal of the battery.

So by disconnecting the ground from the battery, there is no return path electrically to it. All electrical equipment's hot wire is isolated from ground unless there is a direct short, and that should be known anywise as they would have a constant drain on battery.

So, like he said, keep welding ground as close to welding as possible, and that is where the current goes. If at all possible, I prefer to hook ground to the part that is being added, to further reduce any stray ground current going through the frame.
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Old 10-02-2017, 04:14 PM
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I have use the following trick a time or two:
Clamp a scrap piece in the ground clamp.
Hold the scrap piece where you are going to weld.
Strike arc on scrap plate first, then as your welding, weld over
to the frame, tacking the scrap to the frame.
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Old 10-03-2017, 08:08 AM
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Another thing, as I re-read the title saying "Newer", would be to seriously limit heat input into the welding process. Like always with the EPA and emissions laws, in order to get vehicles lighter auto manufacturers look towards metallurgy for stronger yet thinner frame sections. A lot of the new steel frames are like this, and contain a hodge podge of things. Still good weldability, but just know that if too much heat input is used it will soften the frame.
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Old 10-03-2017, 09:32 PM
Fast Orange Fast Orange is offline
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Thanks guys-
All the repairs involve the rack body and lift gate- so no worries about the tinier frames under the new trucks. The frame under a new 3500 Chevy looks like tin foil compared to a 97 F250..
I'm going to go with unhooking the batteries- seems to be the key from what all have said.
It's been about20-25 years since Ive done any stick welding-this ought to be interesting....
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Old 10-04-2017, 12:06 AM
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Speaking as a truck builder, do some research. Look up the builders book the manufacturer puts out. There will be a good and large section on welding frames, what you can and cannot get away with, where you can and can't weld, fillers, acceptable processes, etc.


Chevy's is an Upfitter manual.......https://www.gmupfitter.com/pdflists/view/39
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Old 10-04-2017, 08:56 AM
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All those welding rigs out there, welding on the rear deck, don't do anything. Unless I was welding right next to a bunch of components, or right on the engine, neither would I.
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Old 10-07-2017, 10:23 PM
Fast Orange Fast Orange is offline
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Did the job today- disconnected the batteries completely and kept the ground close to where I was welding.
All went well, no electronic gremlins to deal with and truck owner is happy...
Thanks,Gentlemen
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