So i get home from a 2 week trip and find that my battery light is on and my alternator is not charging. Got a new alternator and nothing changed. Can't find this so called mega fuse that everyone says to check. please can someone tell me where it is. pictures would be great too.

 

side of the main power distribution box.

 

Thats where I have been looking but still no luck.

 

should be two 10mm nuts on the side. I cant remember exactly if it faces the fender or not. I believe it does but could be wrong

 

found the two 10mm nuts that connect the battery to the distribution box, pulled apart the box, still can not find any fuse

 

I will go take a pic of mine

 

there it is. Sorry it was on the brake booster side. Either way this should help. BTW mine is a 98 so things may be different

 

yeah still not there, but thanks for the help

 

follow the positive cable from the alternator....it goes right to the mega fuse.

or check the resistance of the cable from the alternator (disconnected from the alt) to the positive cable (disconnected from the battery). if it is open, the fuse is bad. if it is 0, the fuse is fine

 

it looks like in 07 it may be a fuseable link in the positive battery cable. its hard to tell from the diagram i have. beat way to know is to check the resistance

 

Wirelessly posted (Droid2)

On my 06 it looks like there is a fusible link in the positive cable. Its all covered though, so no way to tell unless its cut open. Probably have to replace the whole cable.

 

My 03 has a fusible link. I had the EXACT same issue as you last month. I wiggled the fusible link and my voltage would swing from 0 -> 12v.

I took the shrink wrap off and it revealed the wire inside was all corroded and turned into green powder, barely making contact. I stripped, and re-soldered the ends and all is well.

 

Found mine on my 98 on the booster side. Tested fuse and was good, cleaned terminals before putting back.
Started engine and still no charge. Tapped back of alternator while running and it charged for 3 minutes then dropped again.
Tapped again, but did not come back up.
Will get yet another warranty alternator and see what happens this time.

 

Where do I find the fusible link located

 

Welcome to the forum

You should start your own thread

Fusible links will be at Starter Relay on the fender but they are year specific, meaning some years Ford used MEGA fuse and other years dual fusible links.

A fusible link "looks like" a regular wire, may or may not have a rubber tab on it.

Google: Ford fusible links

To see pictures of what you are looking for

 

Hi Guys,
I have 2007 ford ranger 3.0 2 wheel drive, The battery light came on and car dies after 20 minutes working because sucks all power from battery instead of alternator,
I have tried 2 alternator but still have problem, Is there any relay or fuse for alternator?
please let me know, thanks

 

Welcome to the forum

Yes, there are fuses and wires you need to check.

Battery Light being on means that fuse is OK, thats the ON/OFF fuse for alternator, just FYI, no Battery Light with Key ON is bad, Battery Light with engine running is also bad, lol.
Fuses #9 and #10 in cab fuse box are for charging system, Battery Light mainly but worth a look.

In 2007 Ford used Fusible Links, instead of fuses on the main power wires for alternator.
So you will need a Volt Meter or a 12volt test light to check them.
With key OFF
Test for 12volts on the B+ terminal on the back of alternator, the Stud with larger wire on it, you don't have to disconnect it, just test if it has 12volts.
If not then its fusible link is bad

Unplug the 3 wire connector on alternator
Test Red wire on that connector, it should have 12volts
If B+ and this Red wire both have no Volts then same fusible link is bad, they share one.
If only Red wire has no Volts then its fusible link is blown.

And just to make sure, while 3 wire connector is removed, test the Gray wire(might also be Green) on that connector, should have little or no Volts
Now turn on the Key(engine off)
That wire should now have 12 Volts, if not then you have a bad wire

Fusible links will be in the wiring harness closer to the engine fuse box

Google: images for ford fusible link

Then click on the link to see pictures of what you are looking for

A fusible link is a short, 6"-8", wire that acts as a Slow Blow fuse, it can heat up when AMPs get high for a short spike without Blowing like a Fuse would, but if AMPs stay high(a short) then they will separate without melting and causing a fire, like a regular wire would, i.e. smoke and burn

 

Thank you for your replies, I did step by step but could not find,
Do you have any picture of fusible link for 2007 ford ranger, nothing show up in google,
Thanks

 

If all the voltage readings are good then it isn't a Fusible link problem, alternator is bad, even if it is new and tested, wiring for alternator is just not that complicated.

Fusible link is just a short wire, 2007 or 1957, some have a rubber ID tag some don't
To find them you need to trace the wire that has the fusible link
They are usually closer to the battery/fuse box end of the wire they are protecting.

And often wrapped up in wiring harness tape or wire loom

But if the wires tested have voltage then fusible link is OK, it is the same as a regular fuse, it works or its blown, there is no middle ground, connected or disconnected

 

I am some how sure is fusible link, because when I bought this truck , they took long wire from fuse box ( right after thick red wire on fuse box under hood ) to tail gate, when I bought this truck , this wire was hanging from under neath on tail gate area and was dangerous . I disconnect this wire by simple removing that red wire right after fuses box under hood.
I can not find the fusible link may be they are covered by black tape in Ford manufacture.

 

So you used a Voltage meter and found no volts on alternators B+ terminal or no volts on Red wire on 3 wire connector?
If you have not done that then you are wasting time looking for, or at, fusible links


Yes, alternator fusible links are are often "inside" wiring harness, so under the tape
Start at battery end of the harness

They are either GOOD or BAD, no maybe it might be........., but..............it would be electrically possible for a connector on one end of fusible link to be corroded, and it would show voltage but could not pass the AMPs needed, longshot but not a "no shot"
Start the engine then use Volt Meter and test voltage on B+, should be above 14volts, if not alternator is bad or Red wire fusible link is, assuming grey wire had 12v with key on(battery light)

 

Thank you guys, There is a connector with 3 wires on alternator, when I connect red wire on this connector to B+ then every thing works. what could be problem now?

 

The 3 wire connector is for the voltage regulator inside the alternator

The fusible link on the red wire is blown, red wire needs 12v to power voltage regulator so it can set correct voltage

Key off engine off
In drawing below,
Fusible Link A is OK since B+ has 12v
Fusible link B is bad since Red wire does not have 12v, unless you short it to 12v(B+)

Fusible Link C is not used on 3.0l, only on 2.3l models

Since you have already cut the Red wire, I assume, then you can splice a fusible link to that Red wire and connect other end to B+ terminal, thats the way Ford Wired it, just did it inside the wiring harness

3 wire connector(red wire)-------new fusible link------------B+ terminal

 

Thanks , Should I look for it on starter side? they are all taped by factory.

 

Yes, they are usually closer to battery/fuse box end than alternator end of wiring

Battery--Power distribution post---fusible link A-----Fusible Link B-----------------------3 wire connector/Alternator
.................................................. ..............\-------------------------------------------------B+/Alternator