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Lighting and coolant warning problems!

3630 Views 10 Replies 8 Participants Last post by  John Koch
Hi all!

We have a 2000 beetle and occassionaly the blue low coolant temp light comes on (apart from the usual warm up period at startup) even when the car has been running for some time and in mild outside temperatures.

The other "strange happening" is that when idling and cold when the headlights are on, the lights "Dim" for a second or so every 20 or so seconds.

I have measured the voltage when this is happening and there is a distinct drop in voltage as if the alternator drops charging every now and then.

Anyone know why these things are happening??? The dealers are no help at all.

Thanks, Mark.
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Our NB also experiences this issue of the lights dimming.

My best guess is that the voltage regulator on the back of the alternator is defective.

The part is about $75, but removing the alternator is a pain, so I haven't gotten around to it just yet.

I have noticed that ours doesn't have this problem when the radio and air conditioning are not in use.
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