14 replies to this topic

[markosparko1994]

my mini set on fire due to an electrical fault, i think on the stalk, the stalk all melted and i now have a new one, much of the headlight wiring inside the car was melted so replaced the melted bits I could see. the rear fog light wiring was also melted so I replaced much of that too. It was all working again but suddenly main beam just stopped working, no lights at all whereas on dipped beam it is fine. I saw smoke and the blue wire to the indicator stalk and to the headlight switch is getting super hot when on full beam, why might this be?

I have standard sealed beam 55w headlights and spotlights but the spots are wired up through a relay which I tested and was working fine.

help much appreciated as I don't want to have to keep replacing wires for them to melt again

thanks, Mark

[markosparko1994]

yeah, replaced the switch

[crispdust]

First check the fuse. If there is enough power going through to melt wires the fuse should be blowing.

Then check the wiring to see if there are any patches of damaged insulation that could possibly be shorting to the bodywork. Usual spots are where the wire passes through the bulkhead / inner wings, or as the wire goes along under the lip of the front, the screws holding the grille on can pierce the insulation of the wires.

Next. Can you disconnect the spot lamps and does it only get hot when the spot lamps are on?

If so Is the relay wired correctly?

Does the relay to the spots have a seperate power feed going back to the fuse box?

I've seen installations where the power feed was coming from the headlight wiring, and then the relay was just being switched on and off. The power for the spots was still coming from the headlight wiring, and the relay was just there because the seperate splot lamp switch couldn't handle any current.

I would do the tests using a current meter in the circuit if you can because it's not the best to keep heating your wiring and switches up. Then If the problem is not obvious I would disconnect everything I can and then connect it back up one step at a time to see what makes the current spike. For example if the bulbs are disconnected it shouldn't draw much current at all.

If you can say where the wiring melted, and didn't melt it may help to localise the problem.

Dan.

[pdaykin]

Is this as a result of something changing eg adding spotlights, reconnecting things incorrectly ?


You need to be careful with this as it can be very difficult to track down.

I had a wiring fault on my headlights which caused lot sof damage to the loom - you couldnt see it all until the loom was entirely unwrapped. The heat had also melted the insulation on adjacent cables. Even when I thought I'd fixed it, turning on other equipment lead to more smoke.

Mine was on a Mk1 so many of the circuits are not fused at all - which doesnt help.

I ended up using a smaller powered battery (didnt give enough current out to melt wires) and an electrical meter to try and work out which circuits were good/bad.

[miniman retford]

Just noticed your user name, quit fitting with your current problem

[markosparko1994]

have had the spotlights on for a qhile now, good point about drawing current for spotlights from the headlight feed but I don't think mine has, better check though. the wires melted from the switch up to the bulkhead, no further as far as I can tell. Have put some fat wires in there now and they haven't melted but the terminal on the back of the switch is still getting pretty warm.

CRISPDUST, what do you mean by a seperate feed going through the fusebox? not sure I have one :/

i can switch spotlights off as they are on a seperate witch too and it makes no difference

hmmm......

[tiger99]

As I have said many times, THERE IS NO FUSE IN THE HEADLIGHT CIRCUIT. It would be dangerous and illegal, as if it blew you would lose both headlights, quite possibly on a very bendy road in a dark night. There is ALWAYS someone with negligible electrical knowledge, who has also never studied a Mini wiring diagram, who trots out garbage about the fuse every time a headlight problem is mentioned. Don't listen to advice like that. It is downright rude to give useless advice like that in my opinion.

You can add seperate fuses for left and right headlights, if you wish, but because of the way the Mini is wired, you would actually need four, one each for left and right dip and left and right main.

As suggested, the cause of the problem could be a wrongly wired spotlight relay (the headlight wiring and dip switch definitely can not handle the current, the wires would get warm, and the switch would be expected to fail), but if the melted wiring stops at the bulkhead it is far more likely that the blue/white main beam feed is shorting to earth at or close to the bulkhead. Melting wires needs more than just the extra load of spotlights, we are probably talking about at least 40 to 50 amps for it to melt rapidly. I doubt that you have 400 watts of spotlights!

Examine the wiring carefully, if the front part of the loom has not melted, there MUST be a short where the melting ends. But, if it has melted, check the bullet connectors behind the grille. One of them (with the blue/white incoming wire of course) may have shorted to earth, but if not, one of the outgoing wires to the headlights will have melted, and the short will be at the light.

[crispdust]

Tiger99,

Sorry, I didn't know about the fuse and the legal requirement, I was at work and didn't have my haynes manual to check. Also I'm only a chartered electronic engineer, but I don't work in the automotive sector, was not aware of the legal requirements and was just trying to help trace the problem.

[hobnob888]

you should of run it through a relay, the switch wires are for small loads, wire them into a relay, then the relay of the alternator to get the the minimal voltage drop and most power. didn't you notice your lights were really dim when you had them on?

My dad can do you a wiring diagram if you like?

Edited by hobnob888, 17 August 2012 - 10:57 AM.

[dave-88_123]

why do some people have to be so rude and put people down over an easy mistake

[1984mini25]

Partly correct about the headlamps not being fused, but the last of the rover minis with the 24 fusebox were.
Anyways, one worth while addition is to add 2 relays for high and low beam. So the new relays deal with the power side of things and the headlamp switch deals with switching the relays.

[tiger99]

dave-88 123,

I will tell you why. Every single thread on this forum about headlight problems, someone chips in and says "change the fuse" or something similar, when, as I have said about 20 times now, it is illegal and dangerous to have a single fuse in the headlight circuit, and no Mini, or any other car which was legally sold in the UK, was ever wired that way. Bad advice is downright annoying, and wastes everyone's time.

Some modern cars, including the very last Minis, do fuse the headlighs, a seperate fuse for each filament of each lamp. A completely different situation.

[dave-88_123]

just because you have said it about 20 times it does not mean everyones seen it you can still correct the person without being rude

[tiger99]

Well, he says he is a chartered electronics engineer, so he should know far better. Basically it was serious professional incompetence.

[jimnali]

just because you have said it about 20 times it does not mean everyones seen it you can still correct the person without being rude

+1