I suspect you have an intermittent /corroded connection
and there is nothing wrong with the alternator
is the alternator belt loose?
I would start by checking and cleaning all the
electrical connections. On the alternator,
(ALL of them) you can spray deoxit gold 100
on the disassembled terminals.
if the connections have turned black, green, etc...
clean all the contamination off.
very often a bad connection will lead you to
believe that an alternator or other part is bad,
even when it's still good...
even a bad connection on the computer
equipment. this may send you on a wild goose
unplug the brainbox, relays, connectors and spray
deoxit gold 100 into all that stuff,
plug and unplug to distribute the contact preservative
around, inside the deepest connections.
going through and cleaning, checking, tightening may well solve
this problem. use only HIGH QUALITY contact
cleaner which is safe on PLASTIC! This is made by
CAIG chemical, and it IS NOT relay cleaner.
Cheap contact cleaner is inferior and may damage
(melt) plastic. Relay cleaner will MELT plastic.
If you have cleaned all this stuff and confirmed that
there are no loose plugs, etc...
your alternator can be tested for free at an auto parts
From what you are describing, I doubt the alternator
is really bad, although I will not say impossible.
The deoxit spray is non shorting and does not interfere
with operation when it's wet. you can spray it and run
it right away, it's non flammable.
Generally speaking, repair shops have no clue when it
comes to automotive electrical, and you are better off
finding an automotive electrical specialist. Otherwise
you may wind up replacing a bunch of parts for no real
verifiable reason, then the problem comes back again.
Even a bad solder connection on the computer PC
board could cause this. bad connections can be found
by tapping, wiggling, etc.. to narrow the area where the