Spent the night and the very early morning in the garage changing the clutch on my wife’s 1997 Mk3 Golf GTI 8V 2.0.

She’s called me saying the battery light is staying on. When I’ve thought about it, I’ve connected the alternator output to the wrong bolt on the starter motor housing. Instead of going to the +ve feed from the battery, it’s connected to an earthing point. (I blame a combination of lack of sleep and all the wiring being black).

Anyway, she’s only a few miles down the road. I’ve told her to avoid using any electrical systems on the way home and I’m hoping the battery lasts the 10 minutes or so that are required. It was charged off the car recently so I’m hoping it has enough residual charge. If not, it isn’t far.

Anyway, that’s the situation but it has me wondering what other systems on the car could be affected by my mistake? I assume that the alternator will be providing a steady charging voltage to the earth of the vehicle. All of the systems (lights, turn signals, dashboard, HVAC blower) all seem to work. Is it possible that the alternator feeding to the vehicles -ve terminal will cause any other issues?

  • This would surprise me, because I'd think you'd be short circuiting the battery in the process ... I guess stranger things. Oct 26, 2018 at 12:57

1 Answer 1


Well, never tried that... :)

But the alternator may possibly survive as the regulator will be trying to keep the voltage up by increasing the rotor current which it will limit to a max valuer anyway.

I don't think on a car that age there will be any other circuits affected, it's not as if you were welding... and blowing electronic flasher units..

So, connect it properly and test the voltages with it running, you will soon know... favourably I hope...

  • I switched the terminals that the wiring was connected to this morning, took at matter of minutes and the car is now working perfectly and the battery light is no longer illuminated. Looks like I got away with this. Oct 27, 2018 at 12:17
  • Excellent, that's nice to hear.
    – Solar Mike
    Oct 27, 2018 at 12:28

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