I just got this Harley a few months ago. It has started something strange. Going down the road the headlight will go off and the volt meter will drop way down then the light andt he volt meter will come back to normal. This may happen every now and again but this morning it didt it aobut 3 dozen times coming to work. Does anyone have any suggestions or maybe where I can get a electrical diagram of this 04 Electra Glide Classic.

 

You can get the electrical diagram in the factory service manual, probably the electrical one. Do the basics and simple stuff first, like cleaning and checking for tightness both ends of the two main battery cables. With a multimeter check the chrging system, using the Stickies in the Tech Electrical section. If that seems OK you may have a problem somewhere. Does you bike have any electrical mods, or high apes, for example - they are infamous for creating electrical problems, especially if they use wiring extensions or internal wiring.

 

It seems stock on the electricals. There are some bolt on parts but nothing with the electical that I can tell. No ape bars. I did change the battery because it was shorted out. That was about 1500 miles ago.

 

There are two possibilities IMHO: an intermittent problem in the charging circuit; or an intermittent electrical problem elsewhere on the bike. Unfortunately many electrical problems are actually mechanical - meaning they are caused by a damaged wire, loose connector, bad ground, that sort of thing. Needless-to-say they ain't always easy to nail down!

If only the headlight and voltmeter shut down, but other lights such as the instruments stay on, that should help isolate where to start checking.

 

Your possible electrical problem is definitely a electrical problem.Sometimes its better to bite the bullet and take bike to a HD technician who can properly diag the problem and in the long run,save you time and money.JMHO

 

When this happens, can you wiggle the ignition switch and see if it changes anything?

 

I will try it.

 

The voltmeter gets power through the Instrument fuse, orange wire and the Headlight through the Headlamp fuse, blue wire. The 2 circuits don't share a common connector but do share a common ground Left hand ground stud.

Here's a guide I made a while back, see if it helps. If anyone see's any errors let me know and I'll make the corrections.
Bill


Harley Davidson Charging System description and testing






Description:
The charging system consists of 3 major parts:

1- An Alternator that generates single phase or three phase alternating current, (AC).
The Alternator has 2 parts:





Rotor:
Attached to the primary side of the crankshaft. The Rotor has a series of permanent magnets and rotates around the Stator at engine speed.

Stator:
Attached to the crank case and has a series of wound wire coils. The Rotor fits over the stationary stator. As the Rotor spins around the Stator the rotating magnetic fields induce Alternating Current in the stationary coils. The Stator’s coils are arraigned so the AC output is either single or three phase.

2- Voltage Regulator, (VR), rectifies the Alternating Current, (AC), from the Stator to Direct Current,(DC), and limits the voltage output to a value close to 14.5 V DC.

3- Battery, a 12V rechargeable storage device used to supply power to the bikes electrical circuits.

As shown in the schematic the charging system includes insulated conductors and connectors carrying current from the stator to the VR through the main fuse to the starter and on to the battery positive. The VR negative lead and the battery negative lead are both connected to Chassis ground.
This system can be checked with a few easy tests using a digital or analog Volt–Ohm Meter.


Testing:

Connectors and cables should be checked and cleaned first. Loose and corroded connectors, terminals and grounds can cause high resistance, impeding current flow. Check cables for broken or rubbed insulation and check continuity to make sure the conductor is not broken inside the insulation.
Coating connectors with dielectric grease will keep moisture out and reduce corrosion.
Use the schematics in the HD Electrical Diagnostic or Service manual to determine the location of additional connectors.


Battery testing:
First check and clean battery terminals, Battery cables and ground connections. To check cables, disconnect one end and Ohm out, wiggle while testing. Cables can and will corrode and the evidence can be concealed under the insulation.
If you are unsure of the battery’s condition charge it fully and take it to an auto parts store and have it load tested.
Voltmeter test:
Connect voltmeter positive to positive terminal on battery and voltmeter negative to battery negative terminal.
12.7 v = 100% charge
12.6 v = 75%
12.3 v = 50%
12.0 v = 25%
11.8 v = 0%
Watch the battery voltage when you start the bike, if a fully charged battery falls below 9.6 volts it’s time to replace it.
If a well charged battery runs down if the bike sits for a short time perform a current draw test. Set your meter to read 10 amps current. Pull your main fuse and insert the meter leads. Here’s a list of components and what current they will draw in milli amps, 1/1000 of an amp) from the 2015 manual:
LHCM 0.5
RHCM 0.5
Speedometer/ IM 0.5
Regulator 1.0
ABS 1.0
BCM 1.0
ECM 1.0
Security Siren 20.0
Radio 0.5
Amplifier 0.5
CB Module 0.5

If the Battery passes all tests check the charging system.
Charging System Testing:
Volt meter set to DCV 20V scale or higher.
With the bike in neutral and voltmeter attached to the battery, start the engine and rev to 3,000 rpm. If the voltage measures 13V – 14.7V the charging system is operating properly. If less than 13V test the Stator first. If Greater than 15.5V test the Voltage Regulator.

Stator testing
Turn the bike off and disconnect the Stator from the Voltage Regulator.
Testing a 3 phase Stator, (A single phase stator is tested in the same manner but the plug will only have 2 sockets).
The end of the connector from the stator has 3 sockets. Set your meter to ohms and connect one lead to the battery negative. With the other lead make contact with the conductors inside each socket. You are checking for a grounded coil winding, each socket should show an open circuit to ground, no continuity.
Now take both meter leads and check resistance between each of the three sockets, 1-2, 2-3 and 1-3. The resistance should be 0.1 – 0.3 ohm.
Next check the Stator’s AC output. Set the meter to ACV 100V scale. With the Stator unplugged from the VR and the bike in neutral, start the bike. Run the bike at 2,000 rpm and check the Stator output between sockets 1-2, 2-3 and 1-3. The voltage should read approximately 32-46 Volts AC, for the 50 amp Stator. Stators with other Amp ratings will be similar.
If the Stator continuity tests to ground and Phase to Phase are good but the output is not the Rotor may be bad.

One other indication that the stator may be bad is if your primary oil smells like a burnt circuit board.

Voltage Regulator Testing

Voltage readings of 15.5V and higher test wire from VR negative to battery negative, if less than 0.5 ohm replace Voltage Regulator.
If the output is less than 13V from the Voltage Regulator to the battery and the Stator output is good, disconnect the output cable from the VR to the Battery. Check continuity between the Voltage Regulator Positive wire and the battery Positive and the negative wire and battery negative. Repair or replace cable if needed. If the cables are good and the Stator tested well replace the Voltage Regulator.

 

Thank you! I will do the testing.

One question: Where is the place the headlight circuit and the charging system share the same lug?

 

A few months ago I found a 2004 used Electrical diagnostic manual pretty cheap so I bought it