Welding to frame Question

Joined
Feb 22, 2004
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I am about to weld on the frame of my 2001 4runner. Should I disconnect the computer from the wiring harness or leave it? I have read both on the internet. I will be using a stick welder if that matters. I already plan to disconnect the baterry cables.
Thanks in advance
Ken
 
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IIRC removing BOTH battery cables is the correct procedure. Might I suggest that you post this in a Tech forum so as to get a better, more knowledgeable response? I doubt that those of us in Arizona know more than the rest of the country about welding. ;)

-Spike
 
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Disconnecting the ECU is good insurance, but probably unnecessary, plus there are a bunch of ECUs in your truck. Disconnect the battery and make sure the welder ground clamp has a good connection as close as possible to the weld site.
 
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gates of hell
There is a chance of electronic damage if any of the circuits are grounded through the chassis (not likely in modern vehicles), and the positive terminal is connected. Basically, you have to create a difference in potential on both sides of the ECU/ECM/PCM/whatever....12v in the battery, and whatever voltage you are welding with on the chassis side. In order for this to happen, you are going to need either a very poorly placed ground (for your welder), and/or a very weak ground....the resistance from the electrode, through the ECU/ECM/PCM/whatever has to be less than the resistance from the electrode, through the frame and back to your welder via the ground cable....like I said....there is a chance. There is also a chance that I will win the lottery, keeping in mind that I don't buy tickets. Make sure you have a good ground close to your work zone, disconnect the + terminal, and you are pretty much eliminating the risk.
 
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Pictures????

Simply put, electricity will always (ALWAYS) follow the path of least resistance. Make sure the path of least resistance leads directly back to your welder via it's ground cable.
 
Joined
Feb 22, 2004
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Thanks for the tips, I ended up disconnecting both battery cables and gounding the welder right next to the area to be welded. After I looked at all the ECUs, I decided that I did not want to disconnect the whole wiring harness. There are ECUs everywhere!!

Here are a couple pics, I had to make the front of the frame rail look like a Tacoma.

frames.jpg


I had to cut of the factory bracket and weld on an end plate with attached nut.

arb4runs.jpg
 
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