not charging ? all dash lights flashing?
 

my 1984 928s seemed to stop charging , I figured alternator? car still starts but all da sh lights are flickering randomly plenty of fuel but flashes reserve then exclamation point just random flashing? showing no charge, I checked battery connections they're good big napa 1000 amp batt. I pulled the alternator it is the French one i'm going to see if they can bench test it , I was wondering if I can switch it for a bosch?thanks!

Sounds more like your warning/caution control module is dying. It's located under the driver footrest. I got a used one off eBay for $30, worked perfectly.

if the warning lights are flashing then it means the alternator isnt charging.
you should be able to swap in a Bosch alternator.

As with any alternator use the makers regulator,
not an aftermarket part as they dont last ,
and will cause other issues

warning/caution control module failure
 

thanks for the info! I pulled the drivers foot rest I never would have known this unit was there! I had a chime dinging under the dash for about a week, must of been letting me know something was going bad. it looks like an electrical storm in my instrument cluster flashing everywhere! I don't think its just my alternator. looking for a warning/caution control module if anyone can help let me know. thanks for this site!

actually when the alternator fails the warning lights will come on at the key test,
and stay on.
NOTE they wont be blinking.

this means the alternator isnt charging. after the engine starts and the waring lights stay on

Might want to clarify what your actually seeing

Roger at 928s R'us carries a good quality Huco brand regulator for an excellent price.
I installed one after my remanunfactured alternator kept eating aftermarket junk regulators, and all is well.