My son had the tires rotated on our '99 F150 4.6 v8 and they sold him an air filter. He told me the battery light has been on since having it done. Checking it out I found a wire connector hanging loose near the alternator but can not locate where it goes. There is a green and a black wire that enters the main harness near where a wire off the brake reservoir sensor also enters. Here is a picture:

 

What does the brake reservoir have to do with the alternator ? You confused me there. Green and Black - Yes , that's alternator. Should be a Yellow wire as well - it's paired with the Green and is the fusible link to the alternator. No yellow wire - No alternator

BTW - That plug in front of the master cylinder is your cruise control deactivation switch - It's red in color. - If that's what your referring to as your brake reservoir sensor.

 

Well , I guess uploading pics here is a thing of the past - hasn't worked in some time

Here yuh go , I just made a new harness a couple months ago. -I put some Alternator,harness,connections shots in an on-line gallery for you to check out -

http://picasaweb.google.com/jbrew393/Alternator

 

Jbrew,

Thanks for the response and pictures. Did my picture not work for you? The wire is not the main alternator wires, but I suspect may have to do with the sensing for the battery light. If you follow the wires from the brake reservoir to where they join the main harness you will see another wire entering the main harness at the same point. If you follow that wire it has a connector that I think should plug in at or around the alternator. Here's the picture again:

 

Yeah that little connector looks like what plugs into the back of the alternator. I remember seeing that when I had mine off.

 

Yea, what's that doin over there ?? It's prolly something new cuz I don't have one of those..? The color (hard to tell) looks like the same as the alternators, but I believe it's a tan w/black stripe. My fuse blocks / wiring is somewhat different than your model, they changed them around from time to time. I have the 98, in 99, wiring took a turn and the fuse blocks were changed quite a bit.

Everything to do with the charging system on my model goes right to what's called the "MEGA Fuse" block ( = Main battery / starter 175 amp copper fuses) on the firewall close to the battery. Nothing runs south of the alternator - On this 98 model anyways..

Yours might, but that connector @ the wires end does look like it connects directly to a component. ? Looks like my connector @the alternator itself. Well somewhat, looks a tast bigger in the pic. Doesn't look like a linked connector to me.

Idunno - confused on that one ...

Let me know what you find out. If your at a dead end, post and I'll see if I can locate that on a service DVD.

BTW - Your shows up fine now ?? Even in the first post. Wonder why it didn't show up before, just a RED X is all I got

Oh well, I'm using a different computer today so maybe that had something to do with it.?

Damn, I hate not having "spellchecker" !! How can I get that on Vista? I need it

 

Yea, I was just told that is "indeed" your alternators battery light wire. Haha thought so, thought the same as NYfordguy posted.

Also noticed your EVR is pointed in the other direction on your model. Never seen that before on the 5fours. Not even on the 01's. Must be a 4six thing

Good Luck