Voltage Regulator Help

[Deye76]

2004 Roadglide, how to check if voltage regulator is working. Can't find a procedure in my service manual.

[nhrider]

Basic test is to read output voltage.   With the engine running, the voltage at the battery should be  between 13.2V and 15 Volts.   If lower it isnt charging...Higher and theres a problem with the voltage regulator.   Replace either way.   Be sure to check for a good ground.

-Dave

[2002classic]

Hi Deye76, I just had to replace my regulator and this was how I tested mine.


Regulator Bleed Test:
Be sure regulator is connected to battery. Unplug regulator connector at engine crankcase. Use a trouble light and touch one probe to a known good ground and the other to the regulator pins, one at a time. If the light glows, replace regulator. You can use a voltage meter the same way, there should be no voltage on either wire.

Voltage Regulator: If your stator is not shorted to ground and has the proper output, your regulator is most likely the culprit. If your stator checks out OK but battery voltage doesn't increase when the motorcycle is running, the regulator isn't doing it's job and needs to be replaced. If the battery voltage goes too high when you rev the motorcycle the regulator isn't limiting the voltage and again it needs replacement.

Stator: If your motorcycle is not charging, you need to check the stator. Locate the plug for the stator on the front of the engine block. Switch the multimeter to OHMS range on the lowest setting, usually 10 ohms. With the motorcycle off, read between the 3 pins or holes in the block. These should show continuity. If your meter is accurate you could read 1 to 3 ohms, but cheaper meters will not be that accurate. As long there is continuity it passes this test.
Now change the setting on the multimeter to the highest OHM range like 100K. Touch one probe to a pin or hole in the engine, the other to the engine case or a metal bolt on the engine. The meter should not move. Try the other pin the same way and it also shouldn't move. If you get any reading the stator is shorted and must be replaced. This requires special tools and you should consider taking it to a shop. If you get no movement on the meter, it's not shorted out so you need to check for output.
To check for output, change multimeter to AC Volts setting over 100 Volts. With the alternator plug disconnected, start the bike. Use the probes (not polarity sensitive) to read between the pins or holes in the engine block. You should read about 20V per 1000 rpm's. At idle expect about 25V, as you rev the engine it will increase to 60 or 70 Volts. If it does your stator is OK, if you get no output the stator is bad and you will need to replace it.

Hope this helps,
Roy

[Deye76]

Many Thanks Roy.