Alternator - again - cause?

[shaunmbenson]

Hey gang

My 1985 3.2 Carrera is about to get its 3rd alternator in a year. All warranteed since the initial replacement. Also replaced battery when i did first fix last year. Also had all work done by excellnt mechanic

Im currently (pun?) im an overcharging situation where it will go from normal to 16 even 17 volts.

Is there anything common that can be causing this? I know the 3.2 alternator arent the most stable but this seems like more than bad luck with the alternator itself

Thoughts? Thanks

[brianlay]

All failed in the same way...overcharging?

[brianlay]

with the ignition on but not running, the alternator light is on?
The correct bulb type is being used for the alternator light?

[brianlay]

Assuming the regilator was changed with each new alternator (it's integrated) then there is a voltage drop on the signal going to D+ on the regulator.
The regulator sees a low voltage and causes the alternator to overcharge.

[shaunmbenson]

Brianlay - no the first failed in the classic stuff faded while on long drives and then the first replacement bith overcharged and then faded. This one the car runs beautifully but the seatbelt light started popping on now and then so i started measuring and found the overcharge
Otherwise I’d have never noticed whereas the other ones were noticeable alternator not working
And yup - bulb correct and on

[shaunmbenson]

What can cause that voltage drop to d+?

[T77911S]

what brand is it

[da Vinci Dan]

Glad to hear you are not getting Charged... for replacements.

[shaunmbenson]

Dont know the brand. And yeah - very glad the warranty is being honoured