Hi

On my GT the alternator charge light comes on when I use my heater.

I can be driving at night and have my high-beam on, and the light in the dash will be fine, but if I put my heater on it goes amber (not fully on but I reckon about 50-70% on), then If I push my brake or turn my indicator on it will come a bit stronger.

If I don't have my lights on and I turn my heater on it comes on.

The light also comes on with my brakes and indicators (but not as strong as my heater)

I know its not a charging issue because it doesn't come on with the lights (the most power sucking thing). A while back we also hooked a multimeter onto it and it was fine (ie the alternator)

I also know it is normal for the charge light to come faintly on on a clubman (something to do with different voltages on either side of it or something - it is a common thing and nothing to worry about)

This is visibly on and I do get worried about it sometimes. Does anyone know why this is coming on? could it be a bad earth somewhere on the auxiliaries? Any ideas on fixing this?

Thanks in advance for your help

Brenton

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The output of your alternator is low enough to trigger the low charge light. When the alternator's output voltage at load drops low enough, the charge will cease to flow to the battery and you are running on battery current ffrom that point on.

It may be the regulator, or it may be a blown diode in the rectifier. You're lucky in that it has worked so far with a problem only showing up when you've got just about everything on. Have the alternator's output checked out.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I had that problem once, it turned out to be a hot joint on the brown alternator output cable. I soldered a new spade lug onto the cable at the alternator end, and it's been fine since.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

That's true, also check the spade or terminal on the other end of the wire at the solenoid.
A voltage drop comes about through high current and dirty connections at terminals. They also get hot.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

The charge lamp on an Lucas Alternator circuit glows dimly because there are differences at Voltage points. B+ and D + should be the same. Check for Voltage drops, bad connections and also exciter diodes faulty. Usually with Faulty exciter diodes the B+ output will be higher than normal.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

Alternator works ok.

Light doesn't come on with headlights (most power draining thing)
Comes on best with heater.

Im thinking it must be a bad connection. I will check terminals and connections and see about giving them a clean.

Thanks everyone for your help. I have somewhere to start now.

Thanks for the explanation convertible mini.

Brenton

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Sounds like you might have a bad connection on your ignition switch circuit to the Fuse box. Check with a voltmeter step by step starting at the Solenoid Pos + side...Ignition switch Pos IN side and then out put side . then. Fuse box hot side (White wire) first then after fuse. This way you should be able to work out where the voltage loss is happening. This is if this car has original Wiring harness.
Another thing I forgot to mention is ... How many amps is your heater fan drawing? It might be drawing too many AMPS due to Fan motor not spinning free enough.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

I will check that when I get some time.

I have no idea what my heater is pulling. I might check that while im at it.

Thanks

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A stock heater? I would be surprised to see it more than a few amps. Compared to the headlights which will be drawing as a minimum 55 Watts each (at 110 Watts combined, that's a little over 9 amps for the pair) plus the ignition system, maybe 5 amps.

The heater is a small fraction of the total load. 2 amps out of a total of 17 amperes.

Unless the heater is defunct or loaded down, then the heater current will be only the final straw I feel. The problem still points back to your alternator and/or the connections to the soleoid and field.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

But remember Mick. The headlights do not run from the ignition circuit. In this guy's case the ignition circuit is where the problem lies.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

That's true. It never hurts to go over the fuse box spades and fuse holders with a little emery too.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

All electricals are stock. Original wiring harness, heater etc. Internally regulated alternator, original lucas style headlights etc.

I should have some time on the wkend to have a look see with it.

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