Hello!
First of all here is a video of the problem:
http://youtube.com/watch?v=G2I3U_vulKcAnd a little back story, now week ago I bought a 1993 Passat B3 1.9TD (AAZ), it didn't had a tach, so I found one with tach, but only thing is that it's from B4 US or UK model. Basiclly it's jumping all over the place. At current time I have checked my wires by the alternator and they looked good, so I'm thinking is there a problem in car or it's cluster.
Any ideas or advice in this situation would be much appreciated.
Is the cluster for an AAZ or a TDI? The tach signal from the alternator is a much higher frequency than most tachometers expect. If it's a TDI tach rather than an AAZ tach it's probably expecting a signal from the crank speed sensor which sends 4 pulses per revolution. The alternator sends out probably 10 times that, which would lead to exactly the behaviour you are seeing.
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