Topic

glad its sorted.

Well!

Well it as short lived used it a few times no great distance went to move it a couple of foot on drive and it cut out same problem, really pushed for time at the moment checked front lights etc can't find any any obvious shorts.

Which fuse is it? You mentioned the 30a one, I assume you mean the one in either slot! or slot2

If so, they goes to the fuel pump relay and the relay block next to the ECU, and the starter relay and from memory also feeds 12v to the passenger compartment fuse board. Not much else.





it could be a dodgy relay or wiring issue near there. Im struggling to look at the diags right now as Im using my phone and in and out of meetings right now, but will come back with more info when I can

Hi yes it is a 30A in slot two on my car, going from wing in they go 30 30 15 10 20 20 15 ?

fuel pump relay and inertia switch (thats the one hidden behind the grill in the top left of the engine compartment)

trace wiring front to back for those and try a relay swap. back shortly... in a meeting right now

also - check for mice!

http://www.mgfregister.org/forum/viewtopic.php?t=17005
some distance down... worth looking at....

Hi thanks for help but don't put yourself out, it is the fuse not the fusible link?

no problem, sorry I cant give undivided attention today but will do my best.

OK fuse 2. as per diag really, problem will either be a dodgy relay or a fault in the loom somewhere. sadly there is quite a bit of car between fuses and the relays, so it might take a bit of finding.

Key areas to look are anywhere the loom passes through metal bodywork, anywhere where there is a sharp corner, near anywhere hot.

It could be a fault inside the loom bundle with no external damage showing, but generally a careful inspection will find it.

You can try narrowing down a little by disconnecting the battery and the with your multi-meter on audible continuity range connect to the far side of the fuse and to earth... wiggle the loom and see if that makes / breaks continuity to earth. That would highlight a wiring fault.

If its a relay problem that may not be obvious without power. Its easiest just to pop a new relay in and see if problem is solved.

Beyond that, Im afraid its a case of laboriously tracing the wiring out from the far side if fuse 2 right through the car which will mean unwrapping the taping along the whole loom step by step.


anyone else want to tag in while I go to next session of meeting?

The best, and safest, way of investigating a constantly blowing fuse is to replace the fuse with a light bulb!

Connect each terminal of the bulb to both sides where the fuse has been removed.

Sounds odd, but it works.

When you have a short circuit the bulb will glow bright. When you remove the short circuit the bulb will go dim again. The brightnes of the bulb determins how much current is flowing.

The bulb will protect the circuit and components as it acts as a current limiter.

Start with something like a 12W 12V bulb. That will only allow 1 amp to flow maximum.

Sometimes just allowing the 1 Amp the bulb permits is enough to "burn off" any short circuit caused by dirt or loose strands at a wire connector.

When the bulb is lit brightly disconnect the relay, and see if it dims. If it does then the relay circuit is the problem. Otherwise disconnect the inertia switch and see what happens.

Using a bulb this way gives you time to find the short, which a fuse will not give.

Thanks for the help guys, the good news it broke down on the drive which is unusual never had that happen before and at this stage it is a fun car. The bad it probably is going to change plans for remap. I changed the relays around and gave them the normal smack only difference is sometimes it flashes hazard lights and warning triangle, and hazard lights and fog light ? Will post when I get a bit more time to look at it and a few more 30A fuses lol