27 replies to this topic

[Quinlan minor]

Before you fit a new fusible link, make sure that it only fractured.

In case there's an underlying problem which will fuse the replacement, too.

[Midas Mk1]

Before you fit a new fusible link, make sure that it only fractured.
In case there's an underlying problem which will fuse the replacement, too.

This! With diag it’s always resolve the cause 1st, not just the effect.

[OlivierW2]

 

Hi,

 

This posting on the forum on the 30/01/2014 might be of some help

 

Spi/mpi Fusible Links & Alternator Wiring

sorry don't know how to post the link.

 

Paddy

https://www.theminif...+fusible +links

That is indeed a good reference for this discussion.

 

 

Thanks Designer and NLinPEN!

I've found the post on the Web archive: https://web.archive....ernator-wiring/ with a picture of the fusible link, same as mine.

 

My alternator is a 65A one, so I should get a 70A or 75A MIDI fuse. But does this MIDI fuses works the same as a fusible link? The fusible links are slow burn and don't blow up immedatly when there's a current spike.

 

I don't want my Mini to end up burning

 

 

 

 

 

Before you fit a new fusible link, make sure that it only fractured.
In case there's an underlying problem which will fuse the replacement, too.

This! With diag it’s always resolve the cause 1st, not just the effect.

 

 

 

Yes, you're both rights!
That's the reason I didn't test my Mini with just a regular wire: if the fusible link is dead, there's maybe an electrical problem. Or maybe ther's no problem, it was just too old. When the electrical problem appeared, I was driving on the highway, at night, with full beam on and the additional long range headlights of my MPI. So it was using more current than is usually does.

 

I've measured approximately the insulation diameter of the wire going from the alternator to the starter motor, and it was 7,17mm. So, I'm still not sure what king of wire it is. Maybe AWG 6? But I'm still not sure.

 

Is there some documentation where all the wire gauges of the car are indicated?

 

I still haven't found "fusible link" in Europe, except in Greece, at 45€

I have found some on Amazon UK, but they don't ship this wires to France.
I'll probably order from some shop in the USA or Canada, anyway, I still don't know what AWG size I'm supposed to buy.

 

And in the meantime, I may install a MIDI fuse, if it's OK.

[OlivierW2]

Hello!

 

So, nobody know the size of the original fusible link? So I could search more where to buy it.

 

Anyway, I've built a 16mm² cable, with a 80A MIDI fuse, and used it in place of the one going from the alternator (B+) to the starter motor. Now the battery is charging! 🤩

 

But the battery lamp in the dashboard isn't working anymore. 😅

 

When my key is on "Off", on the alternator I have around 12V at B+ and 0V at D+.

When my key is on "Ignition", I have around 12V on both B+ and D+.

 

So I've a few more questions regarding the non working battery lamp:

• Is it because I have completely disconnected the original wire going from B+ to the starter motor? The original wire connected to D+ is still there and seems to work.
• Is there a way to easily test the battery lamp, without removing the dashboard?
• Is it safe to drive without this battery lamp working?

Thanks in advance for your help!

Attached Files

•  4.jpg   28K   1 downloads

[OlivierW2]

Hello!

 

So, I've found how to test the battery lamp without removing the dashboard: just remove the "D+" wire and connect it to the car's earth while the key is on "Ignition". My lamp is working fine!

 

But I don't understand some stuff. In the owner's manual of the MPI, about this lamp, it says:

 

2. Battery charging - RED

 

Illuminates as a bulb check when the starter switch is turned to position ’II’ and extinguishes when the engine is started. If the light remains on, or illuminates whilst driving, a fault with the battery charging system is indicated. Seek qualified assistance urgently.

 

How is it supposed to work? Like I said in my previous message, when my key is on "II" (Ignition) and the engine isn't running, I have 12V on the D+ pole. The bulb can't light on when it has 12V on both sides.

Am I missing something?

 

In my first message, I said I replaced the alternator with a new one. The new one isn't an official Rover/Magneti Marelli A115i alternator. It's a generic, noname, compatible one. It looks the same and provide 65A, like the original. I bought it on a french website, selling Mini parts.

Edited by OlivierW2, 02 May 2026 - 01:50 PM.

[sonscar]

When you turn it on the alternator is less than 12v so the lamp lights.When it starts charging it produced voltage equal to the lamp side and so it goes out.Steve..

[OlivierW2]

Yes, but my problem is: the light never turn on.

 

The only time I've been able to turn it on today, was when I disconnected the exciting wire from the alternator (D+) and connected it to the earth car (it's the wire going from the engine bay's fuses box, to the dashboard light, to the diode and then to the D+ of the alternator)

 

Before changing the alternator, the light was working properly:

• ON when key is on "II" (Ignition) and engine not running
• OFF when engine is running

There's probably something I'm missing, but I can't find it.

[NLinPEN]

Okay, so you have installed a new fusible link (your homemade version). Is the alternator charging the battery when the engine is running? With the engine off the battery voltage should be something like 12 Volts, assuming your battery isn't flat. With the engine running this battery voltage should increase to approximately 13.8 Volts when idling, and up to about 14.4 Volts when the revs go up (higher than about 1500~2000 rpm). If the voltage at the battery pins is not increasing with running engine this would mean that you alternator is not working.

[OlivierW2]

Yes, when the engine is not running, my battery is around 12V.

And when the engine is running, it's over 14V: I've measured it directly on the battery terminals, and also my Mini's voltmeter shows it.

Attached Files

•  5.jpg   40.41K   1 downloads

Edited by OlivierW2, 03 May 2026 - 06:14 AM.

[NLinPEN]

Yes, when the engine is not running, my battery is around 12V.

And when the engine is running, it's over 14V: I've measured it directly on the battery terminals, and also my Mini's voltmeter shows it.

Okay. This implies that your alternator works. Usually the alternator gets activated ("excited" is the jargon often used) by a current through the dashboard light. Once the alternator works this current is no longer needed and the light goes out. In your case is the alternator working, but the light does not illuminate. I would not worry about that, especially as you apparently have a voltage gauge on your dashboard and can see that it is working.

[OlivierW2]

Thanks!

I just went for a short drive, getting the engine up to temp and getting some fuel. The whole time the car's voltmeter was above the 13V mark and everything seems alright.

 

Yes, the light not illuminating may not be very important, but it feels like something is weird or missing.

 

Here in France, we have "Contrôle Technique", it's similar to MOT in the UK. I know they check for lights on the dashboard, but I'm not sure if they check if the battery light is working or not. As it's not a safety feature, maybe it's fine.

[Quinlan minor]

 I know they check for lights on the dashboard, but I'm not sure if they check if the battery light is working or not. As it's not a safety feature, maybe it's fine.

It's not a "battery" light, it's a "charging" light.

Should be lit when the engine is stopped and go out after it has started.

It serves to warn if the electical system is draining, and if the fan belt is present and correct (that both water pump and fan, if not electric, are functional).

A red light while running may be your best notice that your head gasket is at risk.

[OlivierW2]

Yes, thanks for correcting me! I said "battery light" because the image on this light is a battery.

 

And you're right, I would prefer to have the light working. Especially since my car is a LHD, and the car voltmeter is on the middle of the dashboard, but close to the passenger side (right), I can't keep an eye on the voltmeter all the time.

 

I hope somebody will have an idea on why my charging light never switch on.