The charge check light in my car has come on pretty much constantly. Car battery ran down while driving back from wherever I was when it failed. End result is alternator (as far as I can tell) is shagged.
Purchased new alternator, hooked up to pre-existing wiring and same problem arises. No charging and battery/charge check light on.
Checked resistance values/continuity between all the wires attached to the alternator. (NB, had multimeter on 200ohm scale and > 100 means it read off-scale)
S - B+ < 1
S - B- > 100
L - B- about 55
L - B+ forget...
Main post - B+ < 1
Main post - B- > 100
Alternator casing - B+ > 100
Alternator casing - B- < 1
I am completely stumped as to wether the above is helpful or not but I am completely stumped as to why a new alternator wouldnt work with wiring that has been working perfectly for quite a while...
Any help will be much appreciated
Edit: had < and > mixed up...
Quote:
Originally Posted by mulligan
(NB, had multimeter on 200ohm scale and < 100 means it read off-scale)
If you had it on the 200ohm scale and it read less than 100 then how is that off scale??
Its probably your charge regulator on the back of the alternator, unless of course that was replaced with the new alternator, good luck with it.
Quote:
Originally Posted by Spool-Up
If you had it on the 200ohm scale and it read less than 100 then how is that off scale??
Its probably your charge regulator on the back of the alternator, unless of course that was replaced with the new alternator, good luck with it.
It means I'm a tool and used the wrong greater than and less than symbols...
The a new one to as far as i'm aware.
check the voltages on the wires. s being sense wire which is connected to a constant 12v and l being light connected to the dash light which gives a voltage to excite the windings once the ignition is turned on.
i would put my money on the light wire
put ur multimeter aside mate much easier with a test light. make sure u have battery to the main battery post on the alt with the test light, make sure the alt caseing has earth. unplug the connector on the back, probe the terminals in the plug, one should have battery, the other should light the testlight dim and bring the battery light on ur dash on with the ignition turned on. i reckon u would probably have lost the battery sense at the plug, in this case start at your fuses and test them with your test light too.
job done
belt is tight.
funnily enough i didnt actually own a test light... i use the multimeter at work... anyway, made up a quick test light.
its basically 100% of what you said i should get.
casing is earthed, post is direct to battery, L lights up the battery check light and S is a full short to battery
anything i have missed about the wiring? may have to get the replacement alternator checked out...
did you check the voltage at the light wire as it isnt fed from the alternator it is supplied from the ignition, through the light than into the alternator which "excites" the windings. Once the alternator starts charging the excite voltage is equalised and the dash light goes out this is why it always comes on for a second when started. Also a good way to check if it's charging turn on the lights and check the battery voltage should be about 14v
I stuck one end of the multimeter into L wire (after disconnectin it from the alternator) and the other on the chassis and got a 12v reading, same with the S wire. the onl difference between the two was the current value, significantly higher on the S winding (as expected given that its essentially a short to the battery).
Im pretty sure the wiring is all good now... and the regulator is brand new. the alternator is second hand but was working on the car it came off....
gahh, i'm stuck :S
Quote:
Originally Posted by TIDYVH
Alt is faulty mate. u have tested the wiring. its nothing complicated. does the light go off when you unplug the alt? its your alt no question
Yeah, light goes off when you unplug the alternator
