13 replies to this topic

[IainStallard]

My Mini Sidewalk keeps blowing the fuse on main beam. I bought the car with the fuse blown but since I replaced the fuse, it solved the problem and I thought nothing of it. However, now it's happening more often. Could there be any reason for this? I have the 24 blade fuse box with a 10amp fuse connected. Not only is it annoying, it's dangerous too so I want to sort it as soon as I can. Any ideas?

[MRA]

When your fuse blows take it a message from your Mini that all is not well..... continue driving it and you may well meet your maker sooner than anticipated..

ALL fuses protect the wiring NOT the device.

Please get it looked at an auto electrician, not you mate who thinks he is because he fitted a set of lamps etc.... this is potentially deadly.

I haven't got a wiring diagram handy, however it always used to be unfused to lamps...

Edited by mra-minis.co.uk, 07 February 2013 - 12:53 AM.

[IainStallard]

When your fuse blows take it a message from your Mini that all is not well..... continue driving it and you may well meet your maker sooner than anticipated..

ALL fuses protect the wiring NOT the device.

Please get it looked at an auto electrician, not you mate who thinks he is because he fitted a set of lamps etc.... this is potentially deadly.

I haven't got a wiring diagram handy, however it always used to be unfused to lamps...

Mine is definitely fused to everything, main beam left, main beam right etc.. I thought it could be a bad earth?

[MRA]

It could be a lotof things..... such as a wire chafingon a part of the body shell, but only in certain circumstances coming into contact and blowing, however a thermal event (fire) is a very high possibility.

It may be nothing more than a loose connection, but do you want to take that risk ? Car fires happen, and when they do if its wiring related they tend to release lots of nasty smoke, that you cannot see through, this makes a crash also highly possible.

Have you got a wiring diagram for your Mini ?

Try to induce a fuse blow by switching items on and off, in other words, at the moment the fault is in the wiring harness/electrical system which is pretty vague, if you narrow it down to a device or a circuit you may find the fault easier.

Poor earths don't often cause fuses to blow, the more likely issue would be that the bulbs dim.

Is it just one bulb or both ? if both then look for the circuit/s that are common

Edited by mra-minis.co.uk, 07 February 2013 - 08:15 AM.

[jaydee]

You shouldnt have a fuse on main beam and possibly you should have a relay switch for them.
This sounds like a messy wiring, which is dangerous and can cause fire so have it checked asap.

[minidave1991-89]

Mine did the same thing. Fuse just blew when the dipped beam was on but this was on the standard fusebox.
The relay was fine. It was very dodgy wiring which the previous owner had done for the alarm system caused an earth short to the bodywork.
Suggest getting in contact with someone either with alot of experience on electrics or an auto electrician (they arent cheap though)

[IainStallard]

It could be a lotof things..... such as a wire chafingon a part of the body shell, but only in certain circumstances coming into contact and blowing, however a thermal event (fire) is a very high possibility.

It may be nothing more than a loose connection, but do you want to take that risk ? Car fires happen, and when they do if its wiring related they tend to release lots of nasty smoke, that you cannot see through, this makes a crash also highly possible.

Have you got a wiring diagram for your Mini ?

Try to induce a fuse blow by switching items on and off, in other words, at the moment the fault is in the wiring harness/electrical system which is pretty vague, if you narrow it down to a device or a circuit you may find the fault easier.

Poor earths don't often cause fuses to blow, the more likely issue would be that the bulbs dim.

Is it just one bulb or both ? if both then look for the circuit/s that are common

Nope, no wiring diagrams unfortunately :/ The fuse blows straight away on the right hand side main beam when you switch them on. It is however only ever the right hand side that blows. A list of fuses for my fuse box found on a forum from here:

Attached Files

•  Mini Fuse Box.jpg   48K   3 downloads

[IainStallard]

You shouldnt have a fuse on main beam and possibly you should have a relay switch for them.
This sounds like a messy wiring, which is dangerous and can cause fire so have it checked asap.

Wiring is not messy in the slightest, to me it seems pretty tidy. I think mine was one of the first to have a 24 blade fuse box fitted so therefore fuses were used on the lights and pretty much everything. I will however check all wiring to the right headlight. Dipped beam has no problems, the problem only occurs on main beam on the right hand light.

[tiger99]

This is one of the few cases in a Mini where having fuses in the headlight circuit is legal, as the left and right are seperately fused. Mostly we get people who are not electrical experts advising others to check the fuse when they have headlight problems, and as I invariably have to tell them, there is never a single fuse controlling both headlights, which means that on most Minis there is no fuse at all. It is good to see that others here are also aware of that very important issue.

However, in this case it seems that seperate fusing is provided, which is good, and it does localise the fault somewhat. Never seen it on a Mini before, and I don't have a wiring diagram for that model, so am at a bit of a loss as to which wires to be checking. The main beams are blue-white on every older Mini, but I suspect that in your case they will be blue-something on the left and blue-something else on the right. The easiest way of finding out which wire is involved is probably to take out the headlight, and follow the main beam wire, which at the light is likely to be blue-white, to the bullet connector which joins it to the main loom. Then follow the wire and look for signs of chafing. It will be that one wire, which will narrow it down somewhat, to between the fuse and the headlight bulb socket. Obvious suspects are at the headlight itself, where the (hopefully grommeted) wire passes through the headlight backshell, at the bullet connector or at the fusebox, but check the places where welded-on metal tags are bent over the loom to keep it in place.

It is not an earth that is causing the fuse to blow, but your earths are likely to give problems at some stage, if they are wired in the usual Mini way, with all front light earths joined at the bunch of bullet connectors just below the bonnet lock. I always advise people to wire the left and right lights to seperate earth points, one on each inner wing, for safety's sake, as you really do not want both headlights to go out suddenly on a winding road in a dark night. It happened to me once, not in a Mini, and I would never take that risk again.

[IainStallard]

This is one of the few cases in a Mini where having fuses in the headlight circuit is legal, as the left and right are seperately fused. Mostly we get people who are not electrical experts advising others to check the fuse when they have headlight problems, and as I invariably have to tell them, there is never a single fuse controlling both headlights, which means that on most Minis there is no fuse at all. It is good to see that others here are also aware of that very important issue.

However, in this case it seems that seperate fusing is provided, which is good, and it does localise the fault somewhat. Never seen it on a Mini before, and I don't have a wiring diagram for that model, so am at a bit of a loss as to which wires to be checking. The main beams are blue-white on every older Mini, but I suspect that in your case they will be blue-something on the left and blue-something else on the right. The easiest way of finding out which wire is involved is probably to take out the headlight, and follow the main beam wire, which at the light is likely to be blue-white, to the bullet connector which joins it to the main loom. Then follow the wire and look for signs of chafing. It will be that one wire, which will narrow it down somewhat, to between the fuse and the headlight bulb socket. Obvious suspects are at the headlight itself, where the (hopefully grommeted) wire passes through the headlight backshell, at the bullet connector or at the fusebox, but check the places where welded-on metal tags are bent over the loom to keep it in place.

It is not an earth that is causing the fuse to blow, but your earths are likely to give problems at some stage, if they are wired in the usual Mini way, with all front light earths joined at the bunch of bullet connectors just below the bonnet lock. I always advise people to wire the left and right lights to seperate earth points, one on each inner wing, for safety's sake, as you really do not want both headlights to go out suddenly on a winding road in a dark night. It happened to me once, not in a Mini, and I would never take that risk again.

I thought it was a bit unusual, but in a good way as it narrows it down more. I will check all wires to make sure they are not shorting anywhere and if gromits are not present, will install them as necessary.

[MRA]

You need to find a wiring diagram.......

A fuse blowing so quickly can only really mean one thing.... its going straight to ground..

[tiger99]

Yes, it will be a fairly solid short, which is better than trying to find one that is very intermittent....

[Dan]

It's usually a short to the headlamp bowl. Especially if you have fitted Halogens as they are longer and sit closer to the bowl.

[IainStallard]

Thanks for all your help guys, I will do some digging on the internet for a wiring diagram while I'm recovering from the flu then when I can I will go check over all the electrics, thanks again