I always disconnect battery and ecu. I worry about high frequency stuff making mischief during welding the van. I know many don't bother. Maybe it's the welding machine I use, maybe it's just fear of the unknown. Doesn't take much effort to disconnect so why not.

Alistair

> On Sep 1, 2015, at 9:26 PM, Steve Williams <steve@WILLIAMSITCONSULTING.COM> wrote:
> 
> Hi,
> 
> I am taking my van in tomorrow for a bit of patching on my exhaust system.
> 
> It suddenly occurred to me that they may be using an electric welder on
> my vehicle rather than a gas welder.
> 
> Is it recommended/mandatory to unplug the ECU if electric
> (arc/mig/tig/etc) welding is being done on a 1991 Westfalia?
> 
> Thanks,
> Steve W.