HELP with 93 GOLF MK3 alternator

The bottom of the alternator (Valeo) has a the two pin plug that the blue wire goes into (dashboard indicator wire) This 2pin plug broke off from the alternator cap.
1. Is this plug attached (part of) to the voltage regulator? 2. If I remove the cap of the alternator can I replace it? and or fix it? 3. I googled and read that the alternator does not work correctly without the blue wire connected. My mechanic says it's only there as an indicator and doesn't affect it. ??
TY in advance for yr help
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