Welding on truck

[4Dodges]

2025 4500 cab n chassis with flatbed, going to install light bar on top of the headache rack and would need to weld a couple brackets on to mount it. Do I need to disconnect both batteries or pull fuses before welding? Thanks

 

[dieselscout80]

When I welded my exhaust tie bar that cracked I didn’t unhook the battery or any fuses.

The battery helps absorb electricity spikes so leaving it connected is a good thing.

Keep your ground clamp as close to your weld as possible, so it doesn’t flow over a large area.

 

[AH64ID]

The commercial body builders guide says to disconnect the batteries before welding.

The battery helps absorb electricity spikes so leaving it connected is a good thing.

I understand that to be completely opposite of what can happen when welding. Leaving the battery connected exposes the electronics to a voltage spike, so disconnecting the battery(ies) isolates the electronics from the spike.

 

[Poolmonkey]

ECUs, infotainment and modules, especially air bag modules are all vulnerable to spike/surge when welding.
Disconnect both battery terminals and as mentioned, keep your ground close to your work. Disconnect modules, ECUs and any other sensitive components in close proximity.
They sell surge/spike/“zap” protectors…

 

[dieselscout80]

The commercial body builders guide says to disconnect the batteries before welding.



I understand that to be completely opposite of what can happen when welding. Leaving the battery connected exposes the electronics to a voltage spike, so disconnecting the battery(ies) isolates the electronics from the spike.

Interesting I hadn’t read that.

Sounds like I will disconnect the battery next time.