New relays = burnt out wires

[georgeyv]

Evening all -

Just switched out my indicator and headlight relay for replacement units (from gsf) - I took the fuse box down, removed the old ones and put the new ones in place. At the same time I removed 2 wires from the fusebox that went to nowhere (I think from a previous stereo and air con units) - when I refitted the fusebox everything was as it should be until I stuck the earth strap back on the battery- there were sparks as I connected them, not hugely unusual but this bus doesn't usually do that so after a few seconds i pulled the earth off and looked in the cab - full of smoke! I absolutely cacked myself and got my extinguisher ready. After a minute or so it cleared up and I inspected what had happened. It seems that the wiring from
The fusebox to the headlight switch has totally burnt out and melted a couple of
Others near it. The headlights worked fine before and fuses were all good.


Could this be the relay? Or have I knocked something and it's shorted?

Cheers for any advice... George.

 

[Moseley]

Have you compared the pin numbers and checked they are the same from one relay to the next?

 

[georgeyv]

Relays are same pin layout/numbers-

On inspection I've noticed that I may have put the wires for the brake warning light on the cluster on the wrong terminals- could that have caused a short like this? The earth from the dash cluster is a mess.

 

[rlepecha]

Relays are same pin layout/numbers-

On inspection I've noticed that I may have put the wires for the brake warning light on the cluster on the wrong terminals- could that have caused a short like this? The earth from the dash cluster is a mess.

It shouldn't do, the brake warning light should work whichever way it is connected up.
Assuming I have understood you correctly.

I would firstly get a copy of a wiring diagram and check you have the right coloured wires from each fuse to relay... It could be that it is a faulty relay, which is highly likely if one of the newer plastic housed ones... These are pretty bad quality.

Sent from my Siswoo C55 using Tapatalk

 

[georgeyv]

After a few hours mucking about I finally got to the bottom of it-
The dash cluster had shorted out on pin 30 of the headlight switch which is permanently live as soon as the battery is connected- that resulted in the thin live wire melting out and the ground wire from the cluster to the chassis melting too. A few other wires were slightly affected so will repair where I can and replace where necessary.

Relays hopefully fine when I get it all back together!