I posted this in the maintenance forum but got no response. I don't think many check there.

I suspected a bad voltage regulator and went through the procedures in the sticky for charging system testing. It says that if you have any voltage between ground and any of the three pins on the regulator's stator connector that the regulator is bad. Mine has 12 volts DC on all three pins. I replaced it with a new regulator and it has the same 12 VDC on all the pins. Replacing the regulator fixed the original problem but the sticky is from 2005 and must not be correct for newer regulators or I have a weird system.

Does anyone know for sure?

 

Stator voltage is AC and should be isolated from ground.

You mush have been measuring output voltage from the regulator. Should be greater than 12V and less than 14.5V DC depending on engine speed.

 

trouble shoot the stator like a three phase motor using the ohm scale with motor not running.
trouble shoot the regulator with motor running at the battery while revving the motor and at idle. reading should be 13 to 15...if lower than 13 or higher than 15 regulator is bad.

 

Maybe I'm the only one that read the sticky on checking the regulator. The stator's AC output is as it should be as are the resistance checks between the three phases and each phase to ground. The info in the sticky says to disconnect the stator from the regulator and check the pins on the regulator to ground. Any voltage present indicates a bad regulator. Mine (both old and new regulator) has 12VDC on each of the three pins. This is with the ignition switch off.

The original problem was an intermittent loss of charging voltage and a red BATT light illuminating. The new regulator (for $200) appears to have fixed it. I'm just trying to find out why my '08 FLHTC doesn't test like the 2005 sticky says it should. I suspect the regulators have changed since then. If that's the case the sticky should be updated but it appears that no one keeps up with that section of the forum any more.

 

the test you are doing is for the diode bridge.

i do not know if that applies to the current (pun) voltage regulators.

if a diode went bad ( and only speaking of the older style VR) the battery could drain when parked "backwards" thru the VR.
another sign of a bad diode is AC voltage measured at the battery

A "diode bridge" is used to convert the sine wave of AC voltage to steady DC. the VR then limits voltage to below about 14.8 DC

mike

 

The only thing I see with the regulator totally disconnected and a meter across the regulator is a meter kick as if a capacitor is charging. There is no way to check each leg of the bridge. The original problem appears to be fixed as it has worked fine for three days. Now it's simply curiosity as why mine acts differently from the procedure in the maintenance forum.

Thanks for the suggestions.

 

newer/older version.

I am well versed in the older charging systems ( and 6 V generator systems), and I like electricity.
But the charging system on my 09 is flawless so I have had no reason to dig into it, the manual, the specs or diagnostics.
If it ain't broke...


Mike

 

My '08 was flawless as well, for 56,000 miles, and I have no complaints with that. Like I said, now it's simply curiosity about the system. I hate to fix things by just throwing parts and money at it but this time it appears to have worked out.