Loss of switched circuit

[Jonessa]

Hi more problems with Molly today, unfortunately I put a dead short in the switched system while fitting a new gauge, I have lost indicators,wipers,stop lamps and fuel gauge. These all run off the one fuse which works when ignition switch is on, all fuses tested and ok, all wiring seems good, short is remove but still all systems are down, any ideas please, could fuse box have given up or is this common problem? Thanks Steve

[geoberni]

Well the only things you haven't mentioned that also come from that fuse are the Oil Pressure light and the Heater Blower.

You've said

all fuses tested and ok,

but quite honestly, I've seen/heard that from so many people over the years, I have to ask, HOW you checked the fuses.....
The one that supplies those circuits is the fuse with the White wires one side and the Green the other.


A Fuse Box doesn't 'give up'; it's just a place with connections to hold the fuses. It can be corroded/tarnished and have high resistance contacts, but other than physical damage, they're fine
Have you got a multimeter?
Do you know how to use one to test voltage and to test resistance/continuity?

Is there battery voltage at the green side of the fuse?

If you put a 'dead short' on the fuse, it should have ruptured, which take me back to How you tested the fuses...

I once wasted an hour fault finding a snag on an aircraft because my fellow electrician misread the multimeter when testing the fuse...

[Jonessa]

Hi yes those 2 don't work either, unfortunately electrics really are not my thing but I do have a meter, so I put feed from a known live to one side of fuse and other side of fuse to an earth on the body and it gave a 12v reading so assume it has not blown, tried both fuses like this. I will clean all terminals and connections tomorrow to see if it's one of them, all connections do look poor and covered with over spray from previous owners respray.

[svenedin]

I would simply remove the fuse in question and test it for continuity on your multimeter. That's the setting that beeps when you touch the two probes together. Put one probe on one metal contact of the glass fuse and the other probe on the other contact. If the meter beeps the fuse is not blown. It sounds like it is pretty much guaranteed to be blown! Clean the contacts up regardless of whether it's the fuse blown or not. The fuse box has storage for two spare fuses which are stored vertically. You may be lucky and there's a spare there.......Otherwise any motor factors sell them, even Halfords and top up the spares slots if empty.

Stephen

[Jonessa]

All sorted now thanks for your assistance, it had blow the fuse and I did put new fuse in but no joy, didn't check the connection before fitting new fuse as it was working fine before but I had but the new fuse into a patch of over spray so no contact cleaned all connections and all good again, a few more poor past repairs sorted as well, she seems to have had a hard life at some, into the next jobs

[svenedin]

Well done! I'm afraid most Minors have been bodged in one way or another but the cars that are left are survivors! A new fuse box is cheap and for the sake of 15 minutes to fit a new fuse box it isn't worth tolerating corroded contacts.

Stephen