Did some welding and now stereo wont work.

[Big-AL]

My mate had a little accident in his nissan wingroad wagon, i was helping him straighten the front out so we could fit a new indicator. i did a tiny little tac weld (with a mig) to hold a washer in place, i disconnected the negative on the battery. when we had finished the stereo wouldnt work. i will pull it out and test with a volt meter and check the fuses etc tomorrow but has anyone else had this happen or got any ideas what might have happened?

[MNC]

This is a complete stab in the dark but is the stereo one of those factory fitted ones fitted with a security code that disables it if pulled out of the vehicle (or loses power)?

[SP450andLE]

This is a complete stab in the dark but is the stereo one of those factory fitted ones fitted with a security code that disables it if pulled out of the vehicle (or loses power)?

My guess too.

Check the owners manual and see if it suggests anything?

[Big-AL]

nah its just a cheapish aftermarket pioneer / sony type cd player. i realise that disconnecting the battery will reset the stereo but it seems like more than that, it looked like it had no power at all.

[kiwipete]

I think the positive should be disconnected as well as the stereo will still get it's earth via the aerial. Possibly as simple as a fuse?

[pradon35s]

wouldn't the aerial not be a earth because the batteries disconnected...?

[churchill]

I don't know the correct procedure but I've tig welded on my car before with the battery connected and everything still worked afterwards. Maybe the stereo is directly connected to the battery and the wire hasn't been reconnected?

[tomsoffroad]

wouldn't the aerial not be a earth because the batteries disconnected...?

Correct Has the stereo got a blade fuse in the back of the head unit. If you disconnected the battery then you should be fine tho

[Big-AL]

had a better look at stereo today, all fuses in engine bay ok, all fuses under dash ok. so pulled the dash apart and stereo out. live 12v ok but earth had no continuity to body of car, so ran the earth to one of the mounting screws and all ok now.

Any ideas why the stereo may have lost its earth from welding? (or disconnecting and reconnecting battery)

[nzhunter]

Where did you have the Earth clamp of the welder in relation to where you were welding?
If it was too far away the charge could take another route and potentially burn out an Earth cable, I would think this was unlikely but could happen. Just make sure you always have the Earth clamp as close to where your welding as possible especially if your welding anywhere near bearings

[slide]

I'm guessing its just coincidental timing. I never 'protect' electronics when (mig) welding, only use good welding practice (good, close earth etc ), and have never had any problems over many years of welding numerous vehicles.
Welding cross current is minimal, so unlikely to damage 12v systems, especially when they're turned off.
my 3cents worth anyways,
Nath

[rangimotors]

do the dash lights still work when you turn the lights on?

[Big-AL]

its not my car, but the guy swears that nothing else stopped working, and he has driven it at night. earth was close to welding, but if i had think of something it may not have been the best connection (i.e semi painted metal). Anyway all sorted now, so ill have to put it down to being just one of those things. But i have learnt lots about good welding practice through my reading on google and peoples replies on here.