swalter

I have a 1992 525i - I have replaced the alternator twice. I replaced it both times based on the fact that I thought the built in voltage regulator on the alternator was bad - couldn't find a rebuild kit. The symptoms: All lighting would pulsate (bright / dark etc.) However I think the problem has now become worse - the car kicks up a trans program code on the dash. Car won't shift and I haveto put it into manual shift. I am assuming that the voltage variation is causing the ECM to put up the code. Any thoughts? I am ready to burn it.

jeffreyb4me

Yes, 'Overvoltage' EGS faults are possible and I'm assuming you've been using Reman. alternators. What brand by the way? In anycase, the Voltage Regulators ARE available for either the Bosch or the Valeo alternators, Valeo regulators being notoriously
faulty 'til 'upgraded' with a later replacement. A good import parts house should have them. Is your battery under the rear seat? '92's were right at a production change.........................................jb.

swalter

Yes - I believe they were reman. and yes the battery is under the rear seat. Can I upgrade the alternator by replacing the regulator in the alternator - or can I actully take the alternator apart with the right tools?

swalter

Also I forgot to mention when I looked a the first alternator I was able to see the connections to the windings from the regulator (what I believe to be the regulator) and they were all soldered in.

Swalter

jeffreyb4me

After removing the alternator, remove the rear cover [4, 5mm screws or 8mm head nuts depending on the brand] & the 6mm and 8mm nuts for the B+ and D+ wires......the voltage regulator is retained by 2 screws and possibly 1 tab screw [brand diff.]
Becareful with the brushes ! ! The Valeo style has a retainer cover that's removed after installation, the Bosch type must be positioned by 'angling' it into place.....You might have seen the 'Rectifier' connections when you last looked. I haven't found a supplier for these and replace the entire unit when the diodes are damaged..............Also, check
the slip rings [what the brushes ride on] for excessive wear [deep groves]. If real bad, you might replace the unit BUT try to find an ORIGINAL
VALEO or BOSCH Reman. alternator........SAME with the Voltage Regultor!!!..NO "OFF" BRANDS ! !...jeffb.