[dawg]

I have noticed recently that when i step on my brakes at idle the voltage will go from 14 volts down to 12?
it never did this before.
could it be a light drawing too much current or will i need a better altenator?
or possible a corrosion problem in the sockets ect?
turn signals seem to draw alot aswell.

 

[dragon0123]

Is it the origianl alternator.?? Mine was doing that as well until I upgraded to a larger one. Could be a combination of that and old wires and light sockets.. after 30+ years the sockets get a lot of crud on them which raises resistance..

 

[JimM]

I've never noticed that from my brake lights, but my voltmeter does tick in time with the turn signals at idle. Mine is a 61 amp, ext. regulator system in pretty good shape.
Always considered it normal.

 

[dawg]

i have a 100 amp alt.
yeah its most likely the corrosion in betting.
ill be changing the rear tail lights and brake lights to LED sequential system this winter .
and a altenator upgrade to a 140 amp 10CS and do away with the external regulator.

 

[go2fast]

i have a 100 amp alt.
yeah its most likely the corrosion in betting.
ill be changing the rear tail lights and brake lights to LED sequential system this winter .
and a altenator upgrade to a 140 amp 10CS and do away with the external regulator.

A 100 amp one wire alternator? That can be a problem because there is no sense line.

 

[dawg]

no its a 100 amp 3 wire altenator

 

[LukeWarm]

How old is the battery?

 

[dawg]

1 year old (battery)
it could also be the new pullys i put on the engine (underdrive)
at idle the car voltage reads 13 volts.
just above idle it reads 14 volts.
combine all the lights at night including brake lights and a pretty stout stereo system and im dropping voltage.
I cleaned the brake light sockets and turn signal sockets and still does the same.
my next step is to increase the size of the alternator wires etc.
then install a 135 amp 3 wire alternator and led sequential tail/brake lights.