Morris Minor Owners Club

Ive fitted an alternator.How do I wire the ign warning light,

Did you not have Instructions with it ??

The Warning Lamp is between the Ign Supply and the Alternator small terminal, usually marked IND.

But I'm not going to say how you do that, because you have given no indication as to what you have fitted, whether it's a kit from a reputable supplier or something you've bodged up from another car, and I don't like only knowing part of what's gone on before giving advice.

If it was a kit it will have been supplied with a small wiring loom and instructions which is the neatest way to do the wiring.

Stephen

If the installation is your own, maybe, if you have a local mechanic, he can visually see what you have and advise.

svenedin wrote: ↑Thu Jan 16, 2025 10:21 am If it was a kit it will have been supplied with a small wiring loom and instructions which is the neatest way to do the wiring.

Stephen

Exactly, which worries me that we have a DIY installation.
Checking their past posts, SEROWMANMICHAEL, mentioned being 50 Years in Motor Trade, but that could just mean selling them...

If it's a Lucas style acr alternator it should have a 3 spade socket/connector in the back, two big spades are power out. Little spade is ign light.

You can connect it up using just female spade connectors but a nicer (read safer) way is to buy the correct plug from a local motor factors or eBay then it connects easily and safely.

If it's not an acr Lucas style unit goodness knows. Depends on which alternator you have.

Steve

Its true I spent all my life in motor trade as a mechanic, never got involved with electrics left to those who know.
You cant see electricity so you cant see where it is!!! Give me an engine/g/box rear axle and I will repair it but nothing electrical.

SEROWMANMICHAEL wrote: ↑Thu Jan 16, 2025 9:42 pm Its true I spent all my life in motor trade as a mechanic, never got involved with electrics left to those who know.
You cant see electricity so you cant see where it is!!! Give me an engine/g/box rear axle and I will repair it but nothing electrical.

Fair enough.

So what are the details regarding this conversion?
Did you have a kit with a connecting cable assembly?
Did it have a Diagram/Instructions?
Does it connect up using the old Voltage Regulator as a substitute Junction box, or does it discard the Regulator and just use a separate terminal box of some sort?
There are a few different ways of connecting it all up, which adds to the confusion for those that don't know electrics.

Maybe this article would be of some use?

If that's no help please tell us what you are trying to install. Although I am a strong believer that the dynamo is the more robust and reliable system (let down by a poor control box) I do understand why people want more charging oomph when they add electrical equipment like heated screens etc.

It looks to me to be a straightforward thing to do providing you have a car with a loom that hasn't been messed around with. The nightmare with any car electrics is when POs have modified the wiring with any old colour wire they happened to have!

If it is any help to you, here's the basic principle: the dynamo system uses the RB106 control box. The control box, which is electromechanical (no electronics inside) determines whether the dynamo output should charge the battery or not. This is necessary so that the dynamo doesn't just carry on charging an already fully charged battery and boil it. When you switch to an alternator the RB106 is redundant because the alternator contains its own electronic "control box" inside it. So the RB106 can become just a junction box and retained to look original despite the fact that it is no longer being a dynamo charge regulator.

As an aside, nobody bothers to maintain their RB106 which contains points (contact breakers) just like the SU fuel pump and in the distributor. They then blame the dynamo (without testing it properly) when the problem is a poorly maintained RB106. The replacement Far East RB106s are total junk which further reinforces the false idea that dynamos are rubbish.

Stephen


viewtopic.php?t=71948

Thanks for all info,the Alternator came from a friend it was one originally from ESM.It is all fitted and wired now thank you.I am thinking of fitting Ammeter .I need a wiring diagram.

SEROWMANMICHAEL wrote: ↑Fri Jan 17, 2025 8:35 pm Thanks for all info,the Alternator came from a friend it was one originally from ESM.It is all fitted and wired now thank you.I am thinking of fitting Ammeter .I need a wiring diagram.

Glad you've sorted it.
As to an Ammeter with an Alternator, the answer is simple. Don't Do It!

Briefly, a voltmeter measures the electrical 'pressure' in a car, while an ammeter measures the electrical current flow.

With a Dynamo, the max current is around 20-30 Amps, so an Ammeter can be a good guide to whether the load on the system is exceeding the output of the Dynamo.
If it reads a slight '+' then the demand for electrical 'power' is still within the capability of the Dynamo. If it reads '-' then you're using power from the Battery.
It saves watching the headlamps getting dimmer before you realise you're exceeding the Dynamo capabilities. The Ign Lamp won't come on because the Dynamo is still working.

With an Alternator, the output is capable of 50-60 Amps, OR GREATER depending on model, so the ammeter needs really thick cable connected direct in line with the feed to the battery to be doing anything worthwhile.
It's pretty pointless, and on a safety side, there's an increased electrical fire risk from having that big thick cable routed around the behind the dash.

A Voltmeter with an Alternator will tell you if the Alternator has failed because the Voltage will drop to Battery Voltage, i.e. below 13v approx.

Bit pointless though, because the Ign Lamp will come on and tell you the same thing, Electrical System Failure.