Charging issue- Help

[Brad110]

D2 TD5


Prep for a school holiday trip. Battery light came on.


Battery seems OK
Orig Alternator not providing charge
Replaced to find red light still illuminated.


Charges at 14.6 -14.8 and reduces and then recovers when all items, lights/ aircon/ rear window demister/ warning lights are turned on, returning to 14.6-.8. From this I am assuming that it is regulating properly.


All fuses are OK.


Red light?


Last work completed Rear shock and Airbag replaced.


Any ideas?

[PhilipA]

The red light measures the voltage. Difference between the battery or connections between and the alternator.
Usually the red light indicates a faulty or zero alternator output but you say the alternator output is OK.
SO
So you have to look for perhaps shorts between the light and alternator.
Regards Philip A

[Brad110]

PM sent

[Brad110]

If it's charging at 14.4~14.8 would the light remain on showing a high charge as a fault?

The Replacement Alternator was rebuilt so is it possible it was set/ regulated for batteries requiring higher V?? Such as AGM?

I vaguely recall an enquiry regarding resetting something to cancel the light??

Regards Brad

[bee utey]

If my memory serves me correctly, the D2 alternator works like the older ones and the charge light provides a trickle current to get the alternator fired up when it spins. A dead diode (one out of six main diodes) in the alternator would cause the red light to glow at slightly reduced brightness and provide only about 1/2 the rated maximum amperage output. Voltage output may or may not be affected. Have it checked by a proper expert.

[justinc]

Hi Brad, possibly an incorrect reg used during the rebuild, I would check there first.
BTW, hope all is well with you lot, must catch up soon :)


JC

[trev]

Make absolutely sure the earth strap to the motor is tight and clean. Rhs of motor near front under wiring harness.Need to remove acoustic cover for access.
I had all sorts of troubles finding this issue. Battery going flat but Alternator charge using mutimeter suggested all O.K.
Seems voltage was there,but not the current.

Trev.