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Charging failure. alternator ok new brushes. Battery OK. No battery indicator light on instrument panel. Does this mean that ECU is not supplying current to rotor coils? How to check and fix?
2002 Suzuki alto Mk3 1.0. Denso Alternator. No volts increase at batt when engine runs. I'll test direct Alt plus to batt minus volts tomorrow.2002 Suzuki alto Mk3 1.0. Denso Alternator. No volts increase at batt when engine runs. I'll test direct Alt plus to batt minus volts tomorrow.
Check for voltage at the small plug at the alternator. There needs to be voltage there in order to turn on the alternator field to make it charge when the vehicle is running. You can test this plug with the engine off and key on. Unplug the connector and check the wiring for voltage. One wire on this plug ( depending on how the manufacturer has the circuit operating ) will use either 5v or 12v to turn on the field. A voltmeter works best for this test as it can easily detect 5v. If there is no power on any of the wires, look for a blown fuse or bad wiringCheck for voltage at the small plug at the alternator. There needs to be voltage there in order to turn on the alternator field to make it charge when the vehicle is running. You can test this plug with the engine off and key on. Unplug the connector and check the wiring for voltage. One wire on this plug ( depending on how the manufacturer has the circuit operating ) will use either 5v or 12v to turn on the field. A voltmeter works best for this test as it can easily detect 5v. If there is no power on any of the wires, look for a blown fuse or bad wiring
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Thanks Paul. I was unaware that the rotor coil supply voltage could be checked with ignition on and the three pin plug removed. Makes sense thinking about it now. Very helpful!Thanks Paul. I was unaware that the rotor coil supply voltage could be checked with ignition on and the three pin plug removed. Makes sense thinking about it now. Very helpful!
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Hi Frank , what make vehicle do you have ? Most newer vehicles the charging system is computer controlled , from early 2000 ! An if there is a problem the PCM turns on battery light via serial data bus message to instrument cluster . All so some vehicles the BCM plays a roll in the charging system , could set a code there !
The fact that so many lights are on most likely suggests an earth fault on the instrument cluster. To check if the alternator is charging - if you can scrounge a voltmeter place it across the battery terminals with ignition off and nothing turned on. You should see around 13.2volts. (a 12v battery is actually 6 x 2.2v lead acid cells hence 13.2v). Now start up and check again - anything significantly more ie. 14.2v+ should indicate that the alternator is charging OK. Alternatively start up and let the engine tick over switch the headlights on then blip the throttle - you should see an increase in brightness which indicates that the alternator is charging. If you have other symtoms such as dim headlights etc they would point to a major earth fault - possibly at the battery terminals but what you describe does initially point to the instrument cluster. __________________
Hi,
That battery light on your instrument panel means the battery is discharging and the alternator does not charging the battery.
Better check your engine, the alternator belt might have been cut off or already missing.
The other one will be is to check the battery terminal if it is properly connected in the battery poles.
If all these are still intact, the problem would be the alternator itself. You have to bring your car to nearest garage to check the charging( voltage ) output of that alternator something might have been broken inside it. Usually the parts inside are the rectifier diode, IC regulator, and the carbon brush.
Hope that helps you out.
Thanks for asking FixYa!
to drop off a battery cable is one old and reliable way to check charging system. if belts are tight and wiring is correct it is time to put a meter to alt and verify output voltage is within acceptable ranges.....
It usually means your alternator is not charging properly. Could be caused by a number of things. Broken belt. Dirty cables, bad connection etc., but is likely a faulty alternator if the belt is ok.
Hi, that would be your alternator needs to be overhauled. The battery light is usually a good indicator that your alternator is not charging. You'll need to get the bearings,brushes, and vacum pump seals replaced. Hopefully the regulator is ok, but they will test this when you get it repaired.
It indicates low or too much voltage. It's either a low battery, a voltage regulator that is going out (it's built into the alternator), or an alternator that is not charging the battery back up. If you know for a fact that the battery is good (not old and it holds a charge ok), pull the alternator and take it to a local auto parts store. Most of them will test it for free.
renew the alternator ,the brushes/commutator are gone .put it on a better becch test with a 60 amp loading minimum and see what i mean or better still remove the regulator housing and inspect the brushes and the commutator and see what i mean
Check your alternator as it sounds like it may be starting to go. The battery light trips when it detects an issue with the charging system. Very rarely, the battery light can trip if there's an issue with the PCM, but this is very rare.
Take a voltmeter with the car off and measure the voltage on the leads of the batter, should be
around 12V+-.2. With the car running, measure again and this time it should
read 13V-14V. If it does read 13V-14V then it means that the alternator
is working. If it is below 12V, then it means your alternator is not
charging the battery properly. If it's above 14V, then it means your alternator
is overcharging and damaging the battery.
2002 Suzuki alto Mk3 1.0. Denso Alternator. No volts increase at batt when engine runs. I'll test direct Alt plus to batt minus volts tomorrow.
Check for voltage at the small plug at the alternator. There needs to be voltage there in order to turn on the alternator field to make it charge when the vehicle is running. You can test this plug with the engine off and key on. Unplug the connector and check the wiring for voltage. One wire on this plug ( depending on how the manufacturer has the circuit operating ) will use either 5v or 12v to turn on the field. A voltmeter works best for this test as it can easily detect 5v. If there is no power on any of the wires, look for a blown fuse or bad wiring
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