Electrical Gremlins fuses blowing any ideas?

[1958trebor]

Hello Gang!
Once again I am asking for assistance with a fault on the Mog, now only 6 months away from its 70th birthday. So, on Thursday, I was driving home and chucked a left indicator out. Trafficator deployed with a healthy 'clunk' Indicator started flashing. Three seconds later, another 'clunk' as the trafficator dropped, then no indicators or fuel gauge. Never happened before. Checked fuses bottom one is burned out. replace same, fine whilst engine off but ignition on. Start engine, instant burned fuse. Where do I start? I took the trafficator out and checked that and it was fine. I've blown 5 fuses trying to fathom out where the short is, Any ideas? Rob.

[simmitc]

Remove all the wires from the fused or "upstream" side of the fuse. Fit a new fuse. Ignition on. Replace the wires one by one until you identify the one that causes the fuse to blow. Isolate that one and continue to check other wires just to make sure that it is only one circuit causing the problem.

You can now see what is working and what isn't. Whatever is not working is the circuit causing the problem, and you can now trace that to find the issue.

[1958trebor]

Ta, did that, Turns out to be the rear offside indicator! One strand of copper wire poking out from the joint. Replaced and working fine now. As ever, in debt to the team and especially Simmitc.

[Blaketon]

Not strictly relevant but having seen how wiring can burn, when there is a serious short, I think a battery isolator is very important. I was lucky that I happened to be there, when it happened with my mother's car and I cut the offending wire before much damage was done. The cut out is bypassed with a small fuse, so that the courtesy light etc works.

[svenedin]

Not strictly relevant but having seen how wiring can burn, when there is a serious short, I think a battery isolator is very important. I was lucky that I happened to be there, when it happened with my mother's car and I cut the offending wire before much damage was done. The cut out is bypassed with a small fuse, so that the courtesy light etc works.

Agreed. I have a wheel type isolator on a battery terminal. If wanted you can unscrew the wheel completely and put it in your pocket and the car is then immobilised.

Stephen

[Blaketon]

The Morris and the 1275 Midget have those but the others all have the red (Motorsport derived) cut out keys, since the batteries are either in the back (Switch under boot floor) or don't have standard terminals. In the case of the Midget 1500, it works out that I can remove the key from the driving seat, as it's in the top of the footwell.

[Bill_qaz]

Not strictly relevant but having seen how wiring can burn, when there is a serious short, I think a battery isolator is very important. I was lucky that I happened to be there, when it happened with my mother's car and I cut the offending wire before much damage was done. The cut out is bypassed with a small fuse, so that the courtesy light etc works.

A bypass defeats the object as a couple of amps will start a fire.
I prefer to completely isolate and have the switch accessible from the drivers seat as is the fire extinguisher.
Like insurance hope you never use it but thankful if you need it