2011 Ford Edge shunting charge due to voltage regulator failure

Generally that indication implies generator failure. Generator failure can come in multiple forms. A faulty ground will cause the generator not to charge and potentially burn it up. A severed phase wind (remember, your alternator is really a three-phase generator with a six pulse front end rectifier set) will cause the light to intermittently come on along with weak charging output. A voltage regulator failure will cause zero field current in the rotor. A brush failure will also cause a generator failure light to come on and stay on. A rectifier failure (any of the six) will cause the generator not to charge properly and turn on the MIL and generator failure indicator (looks like a battery). The condition of the battery can also cause generator failure, if the battery is defective (buckled plates, weak electrolyte, low water, etc.) it will place a very high load on the generator continuously, causing it to 'full field' the rotor which can cause the rotor to overheat and fail. Never run a generator without the battery terminals connected as this will cause it to fail quite spectacularly. Do not attempt to verify output of the generator with the battery terminal leads disconnected.

If generator failure is indeed the cause, find out why. Generators rarely fail. When they do, it usually is caused by poor ground connections, corroded battery terminals, high continuous loads, electrical faults and poorly-wired ancillary equipment, such as head units, amplifiers, inverters, etc. Always check all these out when replacing the generator. Never run a generator without the battery terminals connected as this will cause it to fail quite spectacularly.

That's typical of a low battery. It has enough charge to pull down the starter solenoid (the click) but not enough to crank the engine.

Another possibility is that the starter main contacts are worn down enough so that the solenoid can't bridge them to turn the starter. This usually begins as an intermittent fault and then gets more common.

Then it could be that the voltage regulator built in to the alternator has failed, causing the battery to go flat. To diagnose this you really need a high current ammeter to measure its output.

A crude test is to turn the lights on high beam and hit the starter. If the lights then die, it is the battery. If not, suspect either the starter contacts or the voltage regulator.

If the battery is anything like 3-4 yrs old, it is probably dead.

How old is the battery? This behavior is typical of a dying battery. Either that or the voltage regulator module in the alternator has failed.


A crude test is to start the car, turn the lights on high beam, and have someone watch them as you rev the engine.If the lights flare up with revs, the battery is probably at the end of its life.


If the lights stay dim, the suspect the voltage regulator. It is a common enough failure.

Symptoms of a charging system problem. The charging system comprises the alternator, battery and associated wiring. If the alternator should fail to produce a sufficient or stable enough voltage for the car's electronic systems - due to a wiring short, faulty voltage regulator, or corroded electrical connector, for example - the car will run off the "reserve" in the battery for a short time until the battery is eventually depleted. (The battery itself could also contribute to the problem if it has a faulty cell or for some reason is causing the alternator to put out an excessively high voltage in an attempt to compensate.)

So a couple of quick checks: Measure the battery voltage with the car off. Yours sounds like it will be dead; the clicking while attempting to start is the starter relay not getting enough juice. Then the question becomes: Is the battery dead because of age (fails to hold a charge) or because the alternator isn't charging it? To answer this question, measure the voltage at the battery with the car running. (Jump it or substitute a known good 12V battery.) You should see 14+V. If you only see 12V or less, you're seeing only the current battery charge without any contribution from the alt.

Finally, don't assume because the alt isn't putting out anything the alt is at fault. The wiring harness and electrical connector to the back of the alt should be thoroughly examined. (The wiring connector is a known failure point on early models.) The wiring harness should obviously show no signs of burning, melting or chafing and the battery terminals should be corrosion free and tight. If the harness checks out, remove the alt and have it bench tested. Rebuilding usually gives better long term reliability than chain store bought reman units, I'm told.

Long story short, I suspect the voltage regulator in your alternator failed, the battery gave it's all trying to keep your car running, finally gave up and now you have a dead alt and a dead battery. Don't just install a new battery without doing the alternator voltage output tests.

If you're really lucky it could be as simple as loose or corroded battery terminals.

STARTING YOUR DIAGNOSIS
What happens when you attempt to start the engine? If nothing happens when you turn the key,"http://www.aa1car.com/library/2003/us20310.htm"to determine its state of charge. Many starters won't do a thing unless there is at least 10 volts available from the battery. A low battery does not necessarily mean the battery is the problem, though. The battery may have been run down by prolonged cranking while trying to start the engine. Or, the battery's low state of charge may be the result of a charging system problem. Either way, the battery needs to be recharged and tested.
If the battery is low, the next logical step might be to try starting the engine with another battery or a charger. If the engine cranks normally and roars to life, you can assume the problem was a dead battery, or a charging problem that allowed the battery to run down. If the battery accepts a charge and tests okay, checking the output of the charging system should help you identify any problems there.
A "http://www.aa1car.com/library/2002/cm10220.htm" that is working properly should produce a charging voltage of somewhere around 14 volts at idle with the lights and accessories off. When the engine is first started, the charging voltage should rise quickly to about two volts above base battery voltage, then taper off, leveling out at the specified voltage. The exact charging voltage will vary according to the battery's state of charge, the load on the electrical system, and temperature. The lower the temperature, the higher the charging voltage. The higher the temperature, the lower the charging voltage. The charging range for a typical alternator might be 13.9 to 14.4 volts at 80 degrees F, but increase to 14.9 to 15.8 volts at subzero temperatures.
If the charging system is not putting out the required voltage, is it the alternator or the regulator? Full fielding the alternator to bypass the regulator should tell you if it is working correctly. Or, take the alternator to a parts store and have it bench tested. If the charging voltage goes up when the regulator is bypassed, the problem is the regulator (or the engine computer in the case of computer-regulated systems). If there is no change in output voltage, the alternator is the culprit.
Many times one or more diodes in the alternator rectifier assembly will have failed, causing a drop in the unit's output. The alternator will still produce current, but not enough to keep the battery fully charged. This type of failure will show up on an oscilloscope as one or more missing humps in the alternator waveform. Most charging system analyzers can detect this type of problem.
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