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Wed Jun 04, 2025 12:48 pm

Hello folks, ive got a 84 gti im doing work on, make my daily. my current issue is the alternator is not kicking on although the exciter wire(blue one) to the dummy light on the dash works, light is on always. accessory and driving. Ive got 3 alternators, one from my other 84 gti and the one that came in the car and a brand new one, new one is in the car now, all 3 had the same issue, new battery installed along with new connections. I also replaced the L shaped plug on the alternator because the original one, spades inside the rubber collapsed. the new connector is good and clean. Ive got the cluster out and even tried throwing another cluster in the car to see if that would fix it. fuses and relays have also been replaced. Issue seems to not go away. Im losing my mind and have read every forum ive found 10 pages deep into google search. Looking for some help here.

Thanks

Thu Jun 05, 2025 6:55 am

I would check the whole alternator wiring harness. I had a similar problem with my Rabbit years ago. Found where the wiring had corroded in two inside the casing.

Just a thought for you!!

This should be in the watercooled forum section...

Sat Jun 07, 2025 9:37 pm

Should be a ground strap to one of your upper transaxle to engine bolts.
Has to be clean & tight. Both ends, clean the (-) battery post & terminal.
The other common issue is the brush carrier, it threads into the backside of the alternator. The circular thing with two small screws holding it on.
When one of the two brushes wears below minimum the result is open circuit & dash light on.
but you do state one alternator is new so back to loose or corroded ground.