Charging question

[TechGuru]

May I hijack my own thread for a moment?

Local Craigslist ad for alternator alleged to have been bought "new" from dealer for 2004 truck, truck died shortly thereafter, alternator is for sale for $35. From description, I think it's a 6G.I know, it sounds too good to be true. All that notwithstanding, could it be a replacement for the G4 in my 2002 Explorer?

Thanks, Zeke B.

What model of 2004 truck?

I'd look it up at RockAuto and see if the parts numbers are the same. If they can give you the part number off of it you can put that into RA and if they sell it pull up a list of what it fits.

Actually, lets do that the other way around...

Buyer's Guide : MOTORCRAFT GL8726RM Alternator / Generator
FORD CROWN VICTORIA 1995-1997
FORD E-150 1997-2005
FORD E-250 1997-2005
FORD E-350 1997-2005
FORD E-450 2003-2005
FORD EXPEDITION 1997
FORD EXPLORER 2002-2005
FORD MUSTANG 1996-1998
FORD THUNDERBIRD 1995-1997
LINCOLN TOWN CAR 1995-1997
MERCURY COUGAR 1995-1997
MERCURY GRAND MARQUIS 1995-1997
MERCURY MOUNTAINEER 2002-2005

Buyer's Guide : MOTORCRAFT GL485RM Alternator / Generator
FORD CROWN VICTORIA 1995-1997
FORD E-150 1997-2005
FORD E-250 1997-2005
FORD E-350 1997-2005
FORD E-450 2002-2005
FORD E-550 2002
FORD EXPEDITION 1997
FORD EXPLORER 2002-2005
FORD MUSTANG 1996-1998
FORD THUNDERBIRD 1995-1997
LINCOLN TOWN CAR 1995-1997
MERCURY COUGAR 1995-1997
MERCURY GRAND MARQUIS 1995-1997
MERCURY MOUNTAINEER 2002-2005

Buyer's Guide : REMY 23659 Alternator / Generator (This is the 8 sipe pulley version)
FORD E-150 1997-2001
FORD E-250 1997-2001
FORD E-350 1997-2003
FORD E-450 2000-2003
FORD E-550 2002-2003
FORD ECONOLINE SUPER DUTY 1997-1999
FORD EXPEDITION 1997-2002
FORD EXPLORER 2002-2005
FORD F-150 1997-2003
FORD F-150 HERITAGE 2004
FORD F-250 1997-1999
LINCOLN NAVIGATOR 1998-1999
MERCURY MOUNTAINEER 2002-2005

Buyer's Guide : REMY 23807 Alternator / Generator (This is the 6 sipe pulley version)
FORD EXPLORER 2002-2005
LINCOLN AVIATOR 2003-2005
LINCOLN CONTINENTAL 1995-2002
MERCURY MOUNTAINEER 2002-2005

 

[Zeke Boniface]

Here's an update.

The original alternator is still on the Explorer, still putting out a mighty 12.8 volts, rock solid at any rpm.

I used jumper cables between the alt and battery on hot and ground. No change.

According to the Mitchell manual folks (thanks, TechGuru) there should be 8 - 10 volts on the "I" terminal, engine running. I have 7.7 volts, I'll call that within the margin of error for now, since the alternator is obviously "on".

I looked up the manual for the alternator tester at the parts store, the one that tested my alternator and the new reman as both "good". It states that the alternator test load is 8 amps.

I looked for "2004 f150 alternator" on ebay, and saw that it would bolt up. But it's definitely a different alternator (6G) and would require at least a different plug and probably a different bracket.

I looked around online for just what always gets replaced in a remanufactured alternator; best I could find so far:

clutch pulley
bearings
brushes, springs if available
voltage regulators on Delco/Ford applications
terminal hardware

Everything else is tested or machined to specs, if need be, and it's good to go.

I rummaged around in my unclassifiable stuff drawer and found a serpentine belt tensioner tool that I bought with a bunch of other stuff at the estate auction of an Exxon station owner who was the father of one of my high school friends.

Thanks again, Mr. G. I looked around at the auction for the flathead V8 valve tools you loaned me as a kid, but couldn't find them anywhere.

Zeke B.

 

[TechGuru]

8 amp test load is a joke. Should be at least 50.

If the price of a new/reman alt is a problem maybe you should go ahead and just try replacing the regulator...

http://www.autozone.com/batteries-s...gulator/duralast-voltage-regulator/293130_0_0

https://oreillyauto.com/detail/bwd-...age-regulator/r401/2604691/2002/ford/explorer

 

[Zeke Boniface]

2002 Explorer 4.6 FWD 4G alternator Built 7/01

No voltage at alternator plug for I circuit with key in RUN.

I have spent some time online looking for a wiring diagram for the charging system, I have seen some labeled 2002 Explorer, but I have my doubts. CJB, AKA fuse block under dash, fuses 15, 16, 21 have been removed, inspected, and replaced. No effect. Seems like there should be a fuse for I circuit, but I have not found it.

My alternator plug has two wires, lg/rd and or/lb.

Turn key to run, red battery light comes on, turn key to start, battery light goes off a few seconds after engine starts.

Battery voltage at rest, 12.5, voltage running, 12.8, voltage with headlights on, 12.3.

Alternator seems to be doing something, but precious little. But without voltage to turn it on, amazing that it does anything at all. Residual magnetism?

What do I need to do to get voltage to the I circuit?

FWIW, alternator tests fine at local parts store. These folks are my friends.

Thanks,

Zeke B.

2002 Explorer 4.6 FWD 4G alternator Built 7/01

No voltage at alternator plug for I circuit with key in RUN.

I have spent some time online looking for a wiring diagram for the charging system, I have seen some labeled 2002 Explorer, but I have my doubts. CJB, AKA fuse block under dash, fuses 15, 16, 21 have been removed, inspected, and replaced. No effect. Seems like there should be a fuse for I circuit, but I have not found it.

My alternator plug has two wires, lg/rd and or/lb.

Turn key to run, red battery light comes on, turn key to start, battery light goes off a few seconds after engine starts.

Battery voltage at rest, 12.5, voltage running, 12.8, voltage with headlights on, 12.3.

Alternator seems to be doing something, but precious little. But without voltage to turn it on, amazing that it does anything at all. Residual magnetism?

What do I need to do to get voltage to the I circuit?

FWIW, alternator tests fine at local parts store. These folks are my friends.

Thanks,

Zeke B.

I installed the rebuilt Remy and it charged at 14.2 volts at idle with or without the headlights on. I felt badly about turning in my OEM unit with 128,000 miles as a core, but it wasn't worth $80 to me.

I had taken off the black cover and regulator of the old unit and found considerable wear on the brushes and the inner slip ring. If I had known how easy that would be to check, I would have done it first thing. Even one company that sells slip ring replacements didn't recommend attempting to replace them on a 4G. Some day I will have to find out what that would involve, since replacement on "easier" models looks a bit complex.

I also learned that the alternator tester at the parts store may not know the difference between an alternator that works to specifications and one that barely works at all.

Some of the advice and some of the wiring diagrams elsewhere on the internet purported to apply to a 2002 Explorer were not applicable to my vehicle. That cost me a lot of time. The members on this forum got me on the right track in response to my first post here.

Thank you for your help.

Zeke B.

 

[TechGuru]

Yep, those alternator testers are worthless.

Had one tested from another vehicle years ago when I got suspicious of my voltage gauge being lower than normal, tested ok so I put it back in. Week later I wind up stranded when it quit completely.