hello and please help

[woodjamin]

hi guys please help. 02 explorer xlt not charging battery. have read and read and read and cant figure it out. i have replaced the battery, alternator and starter checked wiring and cleaned grounds. battery just drains right out. i cannot figure this out. any help is appreciated! no 175 amp mega fuse in this truck.

 

[woodjamin]

i am going through the fuse boxes now and pulling unnecessary ones.

 

[woodjamin]

battery light is on. something is weird. horn didnt work when i got the truck. took out horn fuses but when i press the horn buttons i hear a relay clicking coming from the rear passenger side relay box. mice turds in truck. could mice have done this? alternator is getting 12+ volts to the bolt on the alternator.

 

[imp]

@woodjamin
12 volts alternator output is too low. If checked with engine running, the reading is that of the battery, alternator not doing what it's supposed to. Two fusible links are wired into the harness which protect the alternator. One or the other may be open (blown). imp

 

[woodjamin]

Ok i have located the fusible links and from the outside they looked ok. im guessing the only way to know for sure is to cut them open. i am getting the 12.5v when i am on the neg battery terminal and the post on the alternator. i have also noticed that my alternator has 3 prongs in the plug for the regulator while the plug wired in the truck only has 2. thank you for the response.

 

[woodjamin]

also not sure if this is related but when i turn my head lights on the display on my stereo goes out but the music still plays.

 

[96firephoenix]

Ok i have located the fusible links and from the outside they looked ok. im guessing the only way to know for sure is to cut them open. i am getting the 12.5v when i am on the neg battery terminal and the post on the alternator. i have also noticed that my alternator has 3 prongs in the plug for the regulator while the plug wired in the truck only has 2. thank you for the response.

he's got some diagnosis steps in there too...

also not sure if this is related but when i turn my head lights on the display on my stereo goes out but the music still plays.

Next to your headlight switch, there's a dial. Turn it up, and your radio light should come back.

The headlight switch cuts the backlight to the radio, and at night only uses the display's light to illuminate the radio. If your dimmer dial is all the way down, it will turn off the dash and radio entirely.

 

[woodjamin]

ok thank you very much. i turned the dial down so the dome light didn't turn on and didn't even think about that affecting the display. now to work on these links. All signs are pointing towards the links, even the in house electrician at my job has told me to test for continuity. Will do so once it stops raining. What gets me is the previous owner had none of these problems before it sat for 1.5 years with no battery in it.

 

[imp]

ok thank you very much. i turned the dial down so the dome light didn't turn on and didn't even think about that affecting the display. now to work on these links. All signs are pointing towards the links, even the in house electrician at my job has told me to test for continuity. Will do so once it stops raining. What gets me is the previous owner had none of these problems before it sat for 1.5 years with no battery in it.

@woodjamin
Be aware that accidentally connecting a battery backwards, reverse polarity, is likely to burn out one of the fusible links. This might have happened when the battery was installed.

A burnt-out link usually has a gnarly-looking appearance to it's insulation, but not always. Check continuity with the battery NEGATIVE cable disconnected. Remove the connector having the one heavy wire from the alternator, and check continuity between that heavy wire connector and the battery POSITIVE terminal. If open-circuited, link is burnt out. The link is in series in that length of the wiring harness. The other fusible link protects the alternator's Field windings, and may also be burnt out, but it is the less likely. It's continuity may be checked between the alternator connector end and battery positive terminal. It's wire size will be the less thick one, but not the thinnest, which goes from the alternator to the PCM. Wire sizes are #4, heaviest, #14, thinner, #20, thinnest. I can only list wire colors for 2004, but they may be the same in 2002: #4 Black/Orange Stripe, #14 Orange/Light Blue Stripe. imp

 

[96firephoenix]

i turned the dial down so the dome light didn't turn on

are your interior lights refusing to turn off? the ground wires in the door connectors are notorious for internal faults. a lot of us have had to open the wiring boot, and splice new chunks of ground wire into the harness.

This is not at all related to your fusible link problem... just an additional issue.

 

[woodjamin]

Ok thank you for the replies I do not have time today to check but will follow your instructions asap. And my dome lights do turn off by them selves.

 

[woodjamin]

FIXED!
Finally got the time and energy to check out the fusible links. Corroded and broken links were the main issue. One of the links was completely broken off and the other 2 for the alternator were extremely corroded and had about half of the wire strands connected. Battery is now charging @ ~14.1v.