Battery Light Turning on

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Hey guys,

Yet another small problem on my car.

Now the battery light comes on in my car and here are the scenario when it happens.

It started to happen last night when the car was under load stereo up semi loud aircon on lights on etc.

It also happened tonight when i down shifted and on full load aswell.

And also under full load under accelerating.

Now the i don't get any noticable symptons as opposed to flickering lights except tonight i got a little bit of power loss. However the car hasn't cut out.

Now with my old cars the bushings are normally the fault however from what i can see there are no bushings i can replace just a few wires one ground one to the battery and not sure where else.

Now what i'm thinking of testing tommorow is the voltage drop under load at a testing place and see what the go is there.

I also think it may be the alternator going. OR even possible a belt slippage.

I tried moving the alternator to no avail but havnt tested the tension on the belt yet.

Any other ideas because i can't seem to mimic it at idle ever just on take off or acellerating so will be really hard to test for.

[JustCruisn]

The generator line comes into the distribution box on top of the battery. Check the 10mm bolts are tight.
These have been known to get loose connections which causes voltage loss, excessive heat, and even fire.

[h100vw]

Slipping belt, what does it look like? The belt has a tensioner and the alt doesn't move. If it were brushes, I'd expect the light to be on all the time and you'd likely already have been stranded.

Gavin

Hey guys,

Yet another small problem on my car.

Now the battery light comes on in my car and here are the scenario when it happens.

It started to happen last night when the car was under load stereo up semi loud aircon on lights on etc.

It also happened tonight when i down shifted and on full load aswell.

And also under full load under accelerating.

Now the i don't get any noticable symptons as opposed to flickering lights except tonight i got a little bit of power loss. However the car hasn't cut out.

Now with my old cars the bushings are normally the fault however from what i can see there are no bushings i can replace just a few wires one ground one to the battery and not sure where else.

Now what i'm thinking of testing tommorow is the voltage drop under load at a testing place and see what the go is there.

I also think it may be the alternator going. OR even possible a belt slippage.

I tried moving the alternator to no avail but havnt tested the tension on the belt yet.

Any other ideas because i can't seem to mimic it at idle ever just on take off or acellerating so will be really hard to test for.

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Hey gavin i just saw the belt had an auto tensioner looks to be alright.

I will also check the terminals on top of the battery.

I got a load test completed on my car but it charged fine even under load.

Has to be something loose slipping or moving that can't handle the power of everything on.

I will try a bit more

[Umai Naa!!]

Not sure if the MK4s had the clutch hub on the pulley, but these are known to fail on MK5s, etc.

Definately have a look on the fuse box on top of the battery. They're known to come loose over time, arc out, and melt the fuse box.

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Ok so they box was all tight not one loose nut.

Thinking it might be the alternator now but why would it be only under load with everything on

[craig_the_german]

Sounds exactly like what happened to mine when the alternator was dying.

Check all the earths to the battery....even the one under the battery box...just a thought

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Can you explain what happened to yours Craig.

I suck at explaining and if it corresponds to what i get then ill just go get the alternator changed

[craig_the_german]

Can you explain what happened to yours Craig.

I suck at explaining and if it corresponds to what i get then ill just go get the alternator changed

Sure. It started as I was driving along, the charging light would blink on and off.

If you turned the headlights on and pointed them at something (like a wall) you could see the lights pulsing.

Towards the end, the engine would "surge" in time with the lights dimming...was really eerie.

Try putting a multi meter across the battery while it is running, you'll notice it is far less that the 13 or so volts you need and it fluctuates.

My car was running so badly I thought it was the Air flow meter..all sorts of things crossed my mind. Replaced the alternator...car ran like a dream.

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Yep pretty much the same.

How much did you pay for the alternator