Technical What to disconnect prior to welding.

[Robin Banks]

Hello,
I've found someone who will come and weld the wheel arch/engine bay on our 244 2.8JTD based motorhome. What do I need to disconnect in terms of protecting the electrics/electronics? To facilitate access, the battery and battery tray have been removed - as have all the cables which go to the square positive terminal plate - and the plate (which appears to have three fuses in it) itself also removed.
Does anything else need to be removed or disconnected? Electronics totally baffle me. Electrics are not my strongest point - I've rewired my 1934 Morris 10/4 saloon, and a 10 metre sailing boat, but I'm not very up to date on things modern - and the 2007 motorhome is the newest thing I've had.

 

[bugsymike]

Hello,
I've found someone who will come and weld the wheel arch/engine bay on our 244 2.8JTD based motorhome. What do I need to disconnect in terms of protecting the electrics/electronics? To facilitate access, the battery and battery tray have been removed - as have all the cables which go to the square positive terminal plate - and the plate (which appears to have three fuses in it) itself also removed.
Does anything else need to be removed or disconnected? Electronics totally baffle me. Electrics are not my strongest point - I've rewired my 1934 Morris 10/4 saloon, and a 10 metre sailing boat, but I'm not very up to date on things modern - and the 2007 motorhome is the newest thing I've had.

Generally speaking when Mig welding in the past apart from disconnecting a battery earth lead that is as far as I have gone.
However on Motorhomes you have control units for mains hook ups etc. which may need isolating.
The other thing I do is position the earth clamp on a good shiny pice of metal close to the actual welding area so less encouragement for spikes through the system.
If concerned and battery already disconnected, then the ECU leads could be released as a precaustion.
There are protection anti spike clamping tools advertised, although not something I have used or needed fortunately.

 

[ZaphodB]

The other thing I do is position the earth clamp on a good shiny pice of metal close to the actual welding area

This every time.

 

[Robin Banks]

Hello,
I've found someone who will come and weld the wheel arch/engine bay on our 244 2.8JTD based motorhome. What do I need to disconnect in terms of protecting the electrics/electronics? To facilitate access, the battery and battery tray have been removed - as have all the cables which go to the square positive terminal plate - and the plate (which appears to have three fuses in it) itself also removed.
Does anything else need to be removed or disconnected? Electronics totally baffle me. Electrics are not my strongest point - I've rewired my 1934 Morris 10/4 saloon, and a 10 metre sailing boat, but I'm not very up to date on things modern - and the 2007 motorhome is the newest thing I've had.

Thanks for the input - duly noted. Where would I find the ECU to release the leads? Confession time; I know what the letters mean, but apart from that what it actually is - and what it actually does - is to me, in the realms of black magic!

 

[bugsymike]

Thanks for the input - duly noted. Where would I find the ECU to release the leads? Confession time; I know what the letters mean, but apart from that what it actually is - and what it actually does - is to me, in the realms of black magic!

Should look something like this and from memory n/s of engine compartment, others will have more detail.
Note be carefully releasing and refitting connector plugs and only with battery disconnected first. If unsure take further advise as very easy to damage one or more of 100s of connecter pins.
I would only disconnect if welding close to it personally.

 

[Robin Banks]

Thanks for the input - duly noted. Where would I find the ECU to release the leads? Confession time; I know what the letters mean, but apart from that what it actually is - and what it actually does - is to me, in the realms of black magic!

Thanks, appreciate the pic. I'll have a cautious look. The area to be welded is at the opposite side of the engine compartment.

 

[bugsymike]

Thanks, appreciate the pic. I'll have a cautious look. The area to be welded is at the opposite side of the engine compartment.

If you have a good earthing point close to the welding, personally I would do the welding.
However your choice, maybe I have just been lucky.