TEST 3: Making Sure The Voltage Regulator Is Getting Power
The alternator's voltage regulator needs an injection of 12 Volts to get the alternator to start producing a charge.
This voltage comes from the terminal labeled with the letter A of the alternator's 3-wire connector (see illustration above).
Terminal A of the 3-wire connector should connect to a yellow with white stripe (YEL/WHT) wire on the 1997 year model vans.
On the 1998-2003 year model vans, terminal A connects to a orange with light blue wire stripe (ORG/LT BLU) wire.
In this test section, you're gonna verify that there is indeed power (10 to 12 Volts) available in this circuit at all times.
This is what you'll need to do:
- 1
Reconnect the negative (-) battery cable to the battery's negative (-) post,.
- 2
Disconnect the 3-wire pigtail connector from the alternator.
This 3-wire connector connects to the alternator's voltage regulator. - 3
Connect the black multimeter test lead to the battery negative (-) terminal.
IMPORTANT: The multimeter test lead must connect to a clean spot on the battery's negative (-) terminal. - 4
Connect the red multimeter test lead to the female terminal labeled with the letter A of the alternator's 3-wire pigtail connector (see the illustration above).
- 6
Your multimeter should register 10 to 12 Volts DC.
NOTE: Power is present at all times, no need to turn the key to the ON position.
Let's interpret your test result:
CASE 1: The fuse is NOT blown. This means that the alternator's voltage regulator is getting power.
Now, this test result, in conjunction with TEST 1 and 2, let's you now that the alternator on your Ford 4.6L or 5.4L equipped van is bad and needs replacement.
Replacing the alternator will solve the no-charge condition on your Ford E-Series van.
CASE 2: The fuse IS blown. This tells you that the voltage regulator is not getting power.
Without this voltage (12 Volts), the alternator will NOT produce a charge. You'll need to inspect the 18 Gauge brown inline fusible link that protects this wire. More than likely, it's blown.
More 4.6L, 5.4L V8 Ford E150, E250 And E350 Tutorials
There are quite a few 4.6L and 5.4L Ford E-Series van 'how to' tutorials and wiring diagrams that you can check out here:
F-Series Pickups: You can find all of the available tutorials and wiring diagrams for the 4.6L And 5.4L V8 F-Series pickups in this index:
- 4.6L, 5.4L Ford F150, F250, And F350 Index of Articles (at: easyautodiagnostics.com.com).
Crown Vic And Grand Marquis: You can find all of the available tutorials and wiring diagrams for the 4.6L And 5.4L V8 F-Series pickups in this index:
Reader's Real Life Case Studies And Solutions
In this section is input and feedback from all of the folks who have had a similar issue with their vehicle and found a solution. If you're one of them, I want to thank you for sharing your experience with all of us!
If you want to share your repair and/or diagnostic experience, you can use the contact form below.
Real Life Case Study:
Vehicle: 1995 Mercury Cougar 4.6L
Trouble Codes: None
Complaint: LOW CHARGE “...Charge Gauge jumping up and down on the dash. I would have to jump start the car to get it started...”
Test Notes: “..I thought it was a bad battery so I bought a new one, but that did not solve the problem. I probably needed a new one anyway, but it didn't solve the problem...”
“...spent some time researching online and found your webpage and followed the test procedure with my dads Volts meter...”
Repair: REPLACED ALTERNATOR “...after taking off the alternator, I still had O'Reillys test the alternator to be sure I don't mean to doubt your test procedure, but I'm not a professional mechanic anyhoo, the alternator tested bad and man I felt so good i had found the problem. The alternator cost me $167 but at least I did not have to go the shop to get it fixed, thanks dude!!!...”
Courtesy of: Tim M.
If this info saved the day, buy me a beer!
