Alternator Warning Light & ABS OFF Light

[Harvs82]

Hi All,

I've been noticing of late that when I start the car up first thing in the morning, or after its been parked at work all day, after starting up, the battery/alternator light stays dimly lit for about 2.5 seconds and then goes out.

It never comes on whilst driving, or whilst the alternator is heavily loaded with the A/C running and blower on full speed, lights on etc, although I have noticed that when the air conditioning is running with the headlights on, the instrument cluster & climate control lighting is very dim when idling, but as soon as I take off it goes much brighter again.

Tonight I started up after work, and the alternator light was dimly lit, as per above, but the ABS off light also stayed on for a bit longer than usual I thought....

Any ideas what the go is? Is my alternator on its way out? I checked the B+ output and it was around 14.4 volts at idle.

[kopper69]

Whats the battery while the car is off? Whats the voltage when the car is running? How old is the battery?

[Harvs82]

Whats the battery while the car is off? Whats the voltage when the car is running? How old is the battery?

Car running voltage is around 14.3 volts or thereabouts, pretty much identical to the B+ measurement. When not running its sitting on atleast 12 volts, haven't checked for a little while. Battery is 2.5 years old, and when starting, it turns the starter over very quickly, no sluggish starting at all.

[hako]

Probably worn brushes or a slightly dirty commutator/brush combination causing a slowish alternator output. Some alts take a second or two to come up to max output - maybe its caused by age/wear/sticky brush holders/dirt or whatever.
I hope this is your problem as its easily fixed.
Another thought is a bad earth somewhere --- what work has been done to the car lately (may be a clue there).
It would be nice if you could measure the voltage when the lights are dim as in:
"I have noticed that when the air conditioning is running with the headlights on, the instrument cluster & climate control lighting is very dim when idling, but as soon as I take off it goes much brighter again."
That points me to low alternator output or a bad earth.
Hope its simple.