03 Sport Trac won't charge... | Ford Explorer - Ford Ranger Forums - Serious Explorations

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03 Sport Trac won't charge...

Nick26

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Cumberland, RI
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98' 5.0 XLT
Hey Everyone,
My 03 Sport Trac won't charge the battery at all. It started when it just wouldn't start and I replaced the battery and it started but then it died shortly after. So I have recharged the battery (to 12.5v) and replaced the alternator but I still don't get 14v when I start it and as soon as I disconnect the negative lead from the battery the engine dies. I had autozone recheck the new alternator and it works fine. So I did some reading on here and found out about the 175 amp mega fuse but on this truck it's a 120 amp fuse link taped up near the positive battery clamp. So I tested with the multimeter and got continuity between the alternator, both big black/orange wire and the smaller yellow/white wire and that all seems fine but I was still suspicious of the fuse link being corroded to the point that it works at low current but not at high so I totally and I cut it out of the wire and clamped the alternator wire to the battery lead but still have the same problem. I read that when the key is in the on position there should be 1 volt on the green/orange wire that's on the alternator plug but I only get .3v on that wire. Could my PCM be dead?

Also some background info on this is there is an aftermarket alarm I installed on it like 50K miles ago(no problems until now) and about 5K miles ago the lock for the power locks totally stopped working (from all doors) even though i tested the continuity from door to door and the switches and they all seemed good. Even still I disconnected the alarm fearing that it might have shorted something, but I still have the same problem with it not charging and no lock button. Does the same PCM control the locks and the charging harness or are they 2 totally separate computers? I once had another weird thing happen too, the tach all of a sudden didn't work but then came back on after a little more driving. So I don't know if all these things are related... if I have a wiring harness that's getting shorted somewhere or if the computer itself could be dead, but what the odds of that be??

Thanks for any help, I'm desperate to get this thing driving again.
 
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cjones101812

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06 Explorer EB
have you checked fuse #2.6 7.5Amp in Central Junction box??

there are also 2 fusible links you need to check.
 
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eXcali

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98 Explorer XLT AWD 5.0
I've had a replacement alt check out fine with autozone but when I had them exchange it for another it worked fine. I have found that sometimes their test machine, or the operator of it is less than reliable.
 
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Nick26

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98' 5.0 XLT
have you checked fuse #2.6 7.5Amp in Central Junction box??
I visually checked most the fuses but there is still a chance it could be... is that #26 or is there really a #2.6?

there are also 2 fusible links you need to check.
2? Are they right next to each other? In my case there there was a 2 gray wires that ran parallel and couple inches of a brown wire(i think it was) right after that. I cut both of those out(because I couldn't find an open dealer that had the battery cable in).

I bought a new battery cable harness(includes positive, negative, alternator, and starter connections, as well as a couple other little plugs) and I am going to try putting that in tonight, but frankly I don't have much faith this will fix it.
 
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Nick26

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98' 5.0 XLT
I've had a replacement alt check out fine with autozone but when I had them exchange it for another it worked fine. I have found that sometimes their test machine, or the operator of it is less than reliable.

I actually took the first alternator I bought back to them and told them it didn't work (this autozone's test machine was broken so they couldn't test my first one either). But I have since taken what is now my 3rd alternator back to a different autozone and they tested it and said it worked fine. I would be pretty surprised if it was still the alternator after trying 3 different alternators on this truck.
 
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cjones101812

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I visually checked most the fuses but there is still a chance it could be... is that #26 or is there really a #2.6?

it's fuse #6 in the second (which is the Central Junction box) fuse block. (the first fuse block is the Battery Junction box.) you should check the fuses with a meter.

2? Are they right next to each other? In my case there there was a 2 gray wires that ran parallel and couple inches of a brown wire(i think it was) right after that. I cut both of those out(because I couldn't find an open dealer that had the battery cable in).

yes, those are them.
 
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Nick26

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I just finished replacing the entire battery wire harness which includes the starter and alternator cables too and I still have the same problem. Is the PCM the only thing left? Is there any relays anywhere in the charging circuit? I don't have the Ford CD for this truck and can't seem to find it on ebay anymore, did ford crack down on that or something I wonder...

Are the PCM's all different (if I pulled one out of yard) or can any 4.0 SOHC one be flashed with the correct software for my truck?

Also another interesting thing about the green/orange wire. I tested it on my other truck (98 5.0) with the key on and it puts out a constant 12V. So then I tested it on the sport trac again this time connecting the multi meter first and having a friend turn the key to the on position and at first it was getting 12V but was dropping by about a volt a second until it was nothing again.

Any ideas? I need some experts here...
Thanks for everyone's help so far.
 
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OneTRACKowner

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City, State
Houston
Year, Model & Trim Level
2003 sptrac
PCM ford explorer SPTRAC 2003

Does anyone know about the computers?

If you need to replace a PCM you will need to reprog it with the KEY. Otherwise your truck will not start and Also It is very expensive. 400 Plus is the price for PCM and $90-120 is the fee to programe it
 
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FirstChoice

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hey guys, just wondering if you found teh cause of the problem with the sport track, I've tested the alternator the usuall way, basic meter, have confirmed power where it needs to be, B+ batt voltage, white wire batt voltage, smaller wire in alt connector, starts at 12 goes to 1, new battery,
connections clean and tight, fuseable links tugged on.
I've installed 2 brand new alternators and neither of them will charge, I have checked all fuses, connections etc and no way will this truck charge, I tested anoterh explorer same engine etc the exact same way only difference is that alt is charging.
I borrowed a used alt that was known to be good when removed a year ago, that alt will charge but only for a few seconds then it shuts down
Hope u can help....
Mike
 
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Nick26

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the problem with my truck ended up being the wires in the new wiring harness on the plug to the alternator were backwards. compare the color of the wires to your new and old harness at the plug.
 
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FORD MECHANIC MARK

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Pasadena, TX
Year, Model & Trim Level
2003 ford explorer s trac
my friend has a 2003 Ford Explorer Sport Trac that has been having the same issue's we had replaced the battery harness, alternator, and battery it's self with no luck. After further inspection/diagnoses I found the main battery connection that goes to the battery junction box from the battery harness had a poor connection due to corrosion. I hope this helps others with this issue.
 
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