Alternator/Battery Trouble

[WarEagle20]

I've had my Bronco for about 3 months, so I don't know too much about it. I was driving last night and everything just shut down in the middle of the street. My buddies and I had to push it to the side of the road. I'm thinking it's an issue with the alternator, and the battery has had to be jumped twice in the past month.

Just wondering if anyone here had specific ideas about what could be the problem. It's a white '93 with 5L engine. Thanks

 

[BroncoJoe19]

If I had to guess, I'd say you're right, your alternator gave up the ghost.

Here is a quick check.

With a digital volt meter, check the battery voltage across the two terminals, fully charged it will be 12.66 volts.

With the engine running, check the voltage again. It should be a minimum of 13.4 volts. If not.. check your battery cables, that they are clean and tight at both ends, and then re-test. If still not at least 13.4, pull the alternator and replace it.

Your battery may also be shot.

Using a digital voltmeter, simply check across the battery terminals.

You should get 12.66 volts.

Next turn your headlights on for ten seconds and check again.

This dissapates any "surface charge"

It should still be in good shape.

Courtesy Mark v

Battery Charge Table

12.6V or higher: 100% charge

12.4V - 12.6V: 75-100%

12.2V - 12.4V: 50-75%

12.0V - 12.2V: 25-50%

11.7V - 12.0V: 0-25%

11.7V or less: 0% (and probably not capable of being recharged)

If it needs to be charged, charge it up overnight, and check it in the morning, as above.

IF it is dead in the morning you need to rule out if there is something draining the battery or if the battery just doesn't hold a charge anymore, and needs to be replaced. To test the battery, disconnect it, charge it up and let it sit overnight, then recheck the voltage. It should stay at the 12.66 overnight.

 

[Wild-Will]

Quick and easy test for alternator issues. Get the engine cranked and idling. Remove the negative battery cable from the battery. If the engine continues to idle then the alternator is OK and the problem is something else, if it quits then the alternator has failed and must be replaced.

 

[gatokat]

duct tape is right. this is the easiest way to test the alternator. although it sounds like the problem to me. i've had this prob before, good luck.

 

[miesk5]

yo,

One possibility is Loose or Weak Contact at Generator Harness Connector TSB 96-21-4 for 86-93 Bronco & F Series, etc. (Ford still desribes the ALT as the Generator)

Source: by Ford

When a generator fails, there are a few failure modes that may cause heat to be produced at the wiring harness-to-generator connector. This excess heat may damage the female terminals on the wiring harness, resulting in increased resistance. The increased resistance produces more heat. When the generator is replaced, the resistance produced by a damaged connector may damage the new generator and could result in a repeat repair, including installation of another generator. High resistance (caused by a damaged connector) will not go away until the damaged connector is replaced.

Visually inspect the harness-to-generator connector for damage (heat, corrosion, distortion and cracking) before installing a new generator. Install the Generator Wiring Harness Connector Kit (E5AZ-14305-AA) if the harness-to-generator connector is damaged.

The Generator Wiring Harness Connector Kit (E5AZ-14305-AA) contains the following:

One (1) Red Wire Butt Connector

Two (2) Yellow Wire Butt Connectors

One (1) Wire Connector Assembly

One (1) Instruction Sheet (I.S. 6849)

PART NUMBER PART NAME

E5AZ-14305-AA Generator Wiring Harness Connector Kit

Connector, IAR Burn-Up, Ford; "...Due to a design flaw from the factory these units are prone to burn up. When replacing these units it is very easy to spread the wiring harness connectors. When this occurs, an electrical arcing takes place and will burn out the unit and harness. Due to excessive heat buildup at the output terminals the original plug is usually brittle and cracked, this is not something distinguishable by the ***** eye. Chances are it is damaged and not useable. You will notice that OCA IAR units come with a brand new wire plug and installed with dielectric grease..."

Source: by mrreman.com via web.archive.org @ http://web.archive.org/web/20030716101137/http://mrreman.com/downloadsgateway/FORD/MRTSB-FORD-001.htm

Connector, IAR Burn-Up, Ford; "fires allegedly caused by the Ford Alternator. Ford uses a plug connector and not the conventional attachment. Investigators think that this plug connector develops high resistance over time and becomes even more dangerous when it is removed and reconnected..."

Source: by interFIRE @ http://www.interfire.org/res_file/fseab_tv.asp

AND;

Parasitic Draw; Diodes inside the alt could be shorted, thus causing drain, but the it would still put out 12 Volts, and pass the Voltage Output Test, however it could not put out full current, and would fail the Current Load Test.Remove & Charge Battery and take voltage reading (should be around 12.6 volts). Disconnect alternator, then re-install battery for a day or so & then check batty voltage again; if no drain, then diodses are prob the issue. or Take alt it to a parts store where they can BENCH-test it for free. BTW, The voltage should be between 13.0 and 15.0 volts w/engine idling.

Source: by miesk5 at Ford Bronco Zone Forums

Battery Does Not Hold a Charge

Battery drain.

Open or high resistance in wiring.

Damaged regulator.

Generator.

System Does Not Charge

Loose or worn drive belt.

Open/voltage drop in Circuit 38 (BK/O).

Open/voltage drop in Circuit 36 (Y/W).

Open/high resistance in Circuit 904 (LG/R).

Damaged regulator.

Damaged generator battery.