The warning lights are coming on - why?

[Aggie98]

Recently when I drive my 2001 Mexican Beetle both warning lights have been coming on. The car has been running fine. Do any of you have any ideas why this is happening? Any help would be appreciated.

Thanks

[Manfred]

Did you meen the generator and oil-pressure lamp in the "tacho" ?

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1600i Register N° 001

[Aggie98]

Yes. The generator light with the battery next to it and the other light on the upper right side of the speedometer. I belive that it has an exclamation point ( ! ) in a circle.

[Manfred]

Could you meassure the current when the lamps are on ?
Is this only for a short time during driving or are they all the time on now when the engine is running ?
It could be that your voltage regulator is defunct. In this case the current is to high and the effect is that both lamps are on.
Please meassure the value and post it again.

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1600i Register N° 001

[Aggie98]

Manfred,

Thanks for you response. The lamps come on and off at random times. They are not an all the time. I will try to get a voltage reading this evening. Thanks again.

[phade]

This sounds like the alternator or it's internal regulator is on its way out.

I would check the following:-

- Fan belt deflection. This should be between 11mm to 14mm at the centre of the belt with light thumb pressure.

- Alternator brushes. These are located within the black square unit at the rear of the alternator. If these look worn out then replace them (these brushes are the same as 1974-on european beetles).

- Alternator regulator. Check the battery voltage when the engine is running. This should be between 13V to 14.5V. If the voltage is outside this range then the regulator may be suspect.

- Check the condition of the alternator its self. If it sounds noisy or gritty then the alternator should be replaced. The alternator its self is the same as the 51A ones fitted to post 1974 european beetles. Any cheap (brand new) alternator will do, avoid the so-called 75A rebuilt ones since these are prone to premature failure (this is what happened to me after 20,000 miles).

[Aggie98]

I was finally able to check the voltage. With the car running the voltage was 11.6 and it was not increasing. Assuming the alternator is bad can I replace it with a 50 or 55 amp unit?

Thanks,
Keith

[Manfred]

Hello Keith,
11,5 volt are to less. With running engine the currrent should be 13,5 volt.
Unscrew postion 34 (i don't remember the English word for "Kohlen" or "Bürstenhalter") on the picture. Maybe those part is defunct. But also take a look on the whole wiring from the generator to the batterie.
If this don't help, it might be that you need a new generator.
On the bottom you will find the partnumbers.





regards
Manfred

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1600i Register N° 001

[phade]

Those are the alternator brushes (illustrated as item number 34 in the diagram above), which is the black plastic square unit at the back of the alternator. Try changing those first (the will fit any post 1974 beetle with an internal regulator).

If that doesn't cure the problem, then it's usually quicker to replace the alternator. These cost about 60 pounds from GSF in the UK. Any brazilian or cheap 50A or 51A alternator will do (the original alternator on the mexican beetle is a Bosch 51A one). I fitted a brazilian 50A one to mine and have had no problems with it after about 60,000 km.

[Aggie98]

Thanks to everybody for your help. I've ordered a new alternator so I should be up an going in no time.