A weak horn is not uncommon and can be caused by bad grounds between rack
and cross-member and cross-member and chassis. I opted to install a relay,
but you could try a ground strap between rack and chassis.
Increasing the electrical load at idle will always drop the revs since the
power to run them comes from the alternator and that takes engine power.
Maybe your idle speed is just too low. If you have more electrical load
than the alternator can supply then the excess comes out of the battery but
should still maintain around 12v, within reason. To put it another way, if
your engine is dying because of lack of voltage i.e. way less than 10v on
the brown circuit then you either have a ridiculously large load or a
reasonable load that the battery can't handle, but then it would probably be
unable to crank as well.
Weak dash lights - is this the warning lamp(s) are on dimly when they
shouldn't be or the gauge illumination isn't very bright? If the former
then yes, this can be caused by a bad alternator. If the latter then join
the club. The ignition warning light should come on with the ignition, then
go out when the engine is started and is revved to 900+. It should stay out
unless the revs drop below 500. If it doesn't do that then you have a
problem either with the alt or the warning light. If you have a problem
with the alt then the symptom is usually insufficient cranking power.
Slow or non-flashing turn signals are usually another sign that alt output
is low, although that can be caused by problems in the turn signal circuitry
itself as well.
Check the voltage on the brown wire at the fuse-block. It should be about
12.8v with everything off after having been standing for a while. Drop to
10v while cranking. Go to about 14v over 900rpm and not drop much below 13v
with a significant electrical load. 'Significant' in this context means
anything the factory provided, and not some 2kW sound system.
PaulH.
----- Original Message -----
From: Mike Razor <mrazor@mis.net>
To: <mgs@autox.team.net>
Sent: Saturday, August 19, 2000 1:08 AM
Subject: Alternator
> Could a lot of my electrical faults be found in a sick alternator.
> Weak horn, once-in-awhile drop of current, slow death when a lot of
> electrical stuff is brought on line. Weak dash lights.
> THANKS!
> MIKE R
>
>
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