If I'm having some welding done on the coach, can I just disconnect the batteries back at the blue isolator?
If you are going to do it by the book, disconnect both sets of batteries at the ground
and disconnect both computers. The most important thing is to do is have the ground
cable hooked up right by the welding.
Welding checklist (https://www.foreforums.com/index.php?topic=42522.msg426095#msg426095)
Just posting what is in link so it doesn't get lost in future. This is both more and less than what I do. I do recommend no aluminum hi frequency welding.
Scott
Disconnect the following before welding on completed coaches:
U270/U280/U295 - B-21 - Alternator ground at alternator
C-2 - Transmission ground at breakerboard
Allison ECU - Under dash / driver's side / both plugs
ABS - 3 plugs in brake ECU - Power in / Front axle / Rear axle
HWH -All grounds on coach and engine batteries
U240 All of the above except ABS
U300/U320 C-E18 Same as U270/U280/U295 plus:
PEEC-ECM at engine - lower square plug w/ allen head screw (2402)
U300/U320 C-E22 Same as U270/U280/U295 plus:
CELECT-ECM at engine - top plug w/ 2 screws (38459) and round Deutsch plug (2348)
Any coach with Aqua Hot option:
Disconnect A9 red 8 ga and A10 black 8 ga at breakerboard in compartment
Any coach with Primus option:
Unplug all connections on boilers
Disconnect #8 black at control panel inside coach
So the steps I do follow verbatim is to disconnect both grounds on both sets of batteries. I proceed to put the disconnected ground cable on the positive post of the battery. This shorts out the entire coach. There is never a discharge ever when this is done. If there is the negative battery still has a connection to the chassis which must be disconnected. Personally i like being able to disconnect the ground cables in short order for emergency situations. Having multiple grounds on the negative battery buss will prevent quick disconnecting of the batteries. Never the less once the two grounds have been disconnected followed by shorting out the positive post to ground all equipment active in the coach will be shorted to ground. I repeat i'm shorting out the coach, not the batteries. I dont weld on my coach with AC welders or Hi frequency ever. Welder ground clamp is placed as close as possible to the active area. I also like having a chain attached to the coach and laying on the wetted ground. The list I posted prior Im sure would cover all the bases. I also am posting the caution label Foretravel placed near my coach batteries. If anyone has any other input its always welcome
Scott
Thanks for the tip Scott...did this today and it worked with no electrical issues 👍
The use of AC welder I thought wouldn't be a good idea and thanks to you Scott I now
know for sure and don't tig weld either which I can't do as I don't have a tig welder