Have fitted new regulator, but, still does not charge. Need to check output at alternator terminals. Can you send me diagram please

Motorcycles are usually fitted with a permanent magnet rotor type alternator that supplies a 3 phase alternating current to a combined rectifier/regulator, the DC output of which should be sufficient to charge the battery and supply enough current to power all the ancillary equipment.

A fully charged 12 volt battery in good health has a terminal voltage of 13.2 and the output of the regulator should be in excess of that or half for six volt systems.

Some motorcycle systems can be remarkably complex so it is best to use a wiring diagram to aid understanding. Motorcycle batteries won't tolerate a sustained high rate of charge so some systems provide a reduced supply until the headlamp is switched on - just one of the many possible complications that could be encountered with motorcycle electrical systems, ballasted rear lights is another...

Go through the basics.
1 Make sure the alternator is charging (operating properly) by measuring the voltage between earth (battery negative) and the live terminal. It should be greater than 13 volts, less than 15V.
2 Make sure the regulator is being excited. Most modern alternators need to have the dash light working in order to send a minute current to the alternator regulator to kick it into life. If the dash light is out, (fused) the alternator won't work.
3 If the voltage from the alternator live terminal is good, check the voltage at the battery. It should be between 13.5 and 14.8 Volts. If this reading differs from the reading at the alternator output, you have a wiring issue.
4 Wiring issues may include but is not limited to:
a) bad connection at the battery terminal
b) bad connection at the main fuse,
c) bad connection at the starter motor. Some vehicles pick up the main power from the battery cable at the starter solenoid.
d) broken wire, bad connections on the main power lead connection terminals.
Happy hunting!

Not sure but I believe the GMC Yukon has an in line fuse in the charging line. If so the output of the alternator will not get to the battery. One way to check is to measure the voltage, when the engine is running. At above idle it should be over 13 volts. Then measure the battery voltage, it should be almost the same within 200 to 400 mVolts. If not the charging line is open. Also if the alternator charging terminal is the same as the battery (12 to 12.7V) while the engine is running, that again indicates the alternator internal regulator is bad. If you turn on the headlights with the engine running above idle and the alternator output drops over a volt or so, the alternator is bad. This measurement can be taken at the battery plus terminal or the alternator charging output.

Check alternator output and the regulator- the regulator may not be working and the battery got overcharged badly

Due to the nature of the battery technology used with vehicles the alternator is mostly incapable of charging the battery. The car alternator is designed to keep a fully charged battery fully charged and to provide all the power for the car equipment.

The alternator charge rate is regulated by a voltage regulator. Because the alternator output is connected to the battery, the alternator and battery voltage will be the same and the voltage regulator monitors that voltage.

The lower the battery voltage the more output the alternator will produce in order to correct the situation but because a lead acid battery has a high internal resistance to accepting a charge the terminal voltage will quickly rise to the alternator regulated voltage and fool the alternator into thinking the battery is fully charged when the output will drop to the order of just a couple of amps.

Switch on the headlights or a similar load that will lower the battery voltage and the alternator will increase it's output again - but only by the amount of current the headlamps or other load is consuming.
It matters not what the alternator rated maximum output is, it is designed to provide only the necessary current and no more.

The only time an alternator should ever need to produce maximum output is when on a dedicated testbed and then only for a short duration to avoid damaging the unit. Testing the current output on a modern vehicle is not recommended except for the regulated voltage testing and a rule-of-thumb output test where all equipment is switched on and the engine speed raised while the battery voltage is monitored.

Most modern alternators use an internal voltage regulator but a few systems use a separate voltage regulator. No alternator rebuild would be complete without a regulator test and probably a new or replacement regulator, which is where the majority of charging system problems are, or the brush gear.
Assuming the wiring is ok, no alternator should suffer any harm if the voltage regulator and auxilliary diodes (if fitted) are in good order though fitting a defective or a discharged battery can cause it to overheat and be damaged.

The alternator usually just about stops producing an output when the battery voltage is in the region of 14.5/14.8 volts.
Your description indicates the voltage regulator is not working correctly - unless 40 amps was being consumed by the car equipment the alternator should not have been producing 40 amps.. I suggest you also have your battery tested

It sounds like you have done a whole lot of replacing and not much "diagnosing". Did you chech for battery voltage at the alternator? There should be battey voltage at the large Black/Orange wire that is on the B+ terminal of the alternator. This wire should have voltage all the time. If there is no battery voltage, you most likely have a burned fusible link at the starter relay area.
There should also be voltage at the "S" terminal with the ignition on. If there is no voltage, then check for voltage at the "S" terminal of the voltage regulator. If there is no voltage at the "S" terminal on the voltage regulator then check the "I" terminal on the regulator for voltage.

NOTE: The voltage on the "S" terminal should be 1/2 that of the voltage on the "I" terminal.

If there is voltage on the "I" terminal, make sure your voltage regulator is grounded properly to the fender and retest to see if it is charging the battery. If it is still not charging, disconnect the regulator connector and connect a jumper between the "A" and "F" terminals of the connector. Start the engine. The alternator should now be charging the battery at high voltage (usually over 15 volts) If it does, replace your voltage regulator. If it does not, then you need to check your wiring between the voltage regulator and the alternator.

Please also review this article:

What Else Could Be Wrong?

it should notgo over 14 1/2 volts.

Get free DTC codes scan from Autozone. I think you will get DTC code 1246 - System Voltage Malfuction.

The I (indicator) (BAT light) wire activates alternator field circuit.

The heavy B wire circuit sends current to the battery for charing and to run the car.

The S circuit helps control the amount of charge. I suspect yours is not controlling. This car has the PCM (engine computer) help control the output and turn the BAT light on when under or over charging.

SECTION 414-00: Charging System - General Information 2003 Windstar Workshop Manual
DESCRIPTION AND OPERATION Charging System This vehicle is equipped with a powertrain control module (PCM)-controlled "smart charge" charging system. The PCM-controlled charging system is a system whereby the PCM determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The PCM-controlled charging system is unique in that it has two uni-directional communication lines between the PCM and the generator/regulator. Both of these communication lines are pulse-width modulated. The GEN COM line communicates the desired setpoint from the PCM to the voltage regulator and the GEN MON line communicates the alternator load condition to the PCM. The third pin on the voltage regulator, the A circuit pin, is a dedicated battery voltage sense line.
-------------------------------------

Charging system malfunction (high or low system voltage)

possible causes:

• A circuit 35 (OG/LB).
• A circuit fuse link.
• B+ circuit 36 (YE/WH).
• B+ circuit fuse links.
• Generator.
• PCM
• GEN-COM circuit 586 (RD/PK).
• GEN-MON circuit 585 (VT).

-----------------------------------------------------------------------------------
Generator The generator (10300) on this vehicle is monitored and controlled by the powertrain control module (PCM). The PCM monitors the voltage regulator and sends a duty cycle command back to the voltage regulator to regulate the amount of field current supplied to the generator. The generator has an internal voltage regulator. The generator and voltage regulator are installed as an assembly.
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I'll send wiring diagram tomorrow.

please rate

yes it could be

check your battery 1st , then check the stator a/c output

• 10 or 16 Amps DC regulated for charging
battery
• Two black leads (C) from stator
• Yellow connector (D) with two pin
terminals
• Two yellow leads (E) to regulator-rectifier
(F)
• One red lead (B) from regulator-rectifier
to red connector output lead (A)
• 10 and 16 Amp systems use the same
stator, color coding and regulator-rectifier
• Alternator output is determined by the
flywheel alternator magnet size


The stator and regulator-rectifier are the same
for the 10 and 16 Amp systems. The system
output is determined by the flywheel magnet
size.
Test Alternator Output
1. Temporarily disconnect stator wire
harness from the regulator-rectifier.
2. Insert RED test lead (A, Figure 28) into the
V ω receptacle in the meter.
3. Insert BLACK test lead (B) into COM
receptacle.
4. Rotate selector to AC Volts position.
5. Insert RED (A) and BLACK (B) test lead
probes into output terminals (D & E) in
YELLOW connector (C). (Test clip leads
may be attached to either terminal).
6. With the engine running at 3600 rpm, the
output should be no less than:
• 20 volts - 10 Amp System
• 30 volts - 16 Amp System
7. If No or Low output is found, check for
bare wires or other defects. If wiring
defects are not found, replace the stator.
voltage depending on alternator type and magnet size

then check the regulator / rectifier , make sure it is grounded properly

make sure battery earth lead is good

i suspect loss of bat voltage is letting the afterfire solenoid close off the main jet

let me know model and type codes off engine & i will try help further

cheers

remove the positive battery connection and check continuity from the cable terminal to the output on the alternator. you can go to autozone.com to view wiring diagrams. register and enter your car. then select repair guides. also, has the battery been tested and found good?

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