charging system fiasco

[primordialpaul]

It doesn't matter which test lead you use. It will either read as a positive number or a negative number (ie 12V or -12V), but it will the same number of volts either way.

I don't know that either the GRN/RED or the red/red 'ish wires are you problem. I'm just trying to explain what the video was saying.

Im under the impression that isnt my issue, that or wherever its dropping voltage is stemming from somewhere else ive tried all the suggested coa's with no definitive results taken apart both connectors to trave that wire and it and pins all seem intact. If it was grounding out and is in fact a ground i dont see what it could possible affect, that and the fact that the light goes off when the connector is detached from alt all seem like that circuit is operational. Im at a loss.

 

[MAS Tequila]

When you jumped it from the connector at the firewall to the alternator did you unplug the existing wire?

If you have voltage before it goes into the trans harness connector but not after, then you have the same issue I had.

Unplug the green/red wire from the alternator, connect a jumper, check the jumper for voltage, then connect it to the alternator.

That's what worked for me.

As far as the charging system being different between the 5.0 and the 4.0's goes, just remember that Ford uses the same parts across most platforms.

You may be surprised how much interchangeability there is between Ford vehicles.

 

[primordialpaul]

When you jumped it from the connector at the firewall to the alternator did you unplug the existing wire?

If you have voltage before it goes into the trans harness connector but not after, then you have the same issue I had.

Unplug the green/red wire from the alternator, connect a jumper, check the jumper for voltage, then connect it to the alternator.

That's what worked for me.

As far as the charging system being different between the 5.0 and the 4.0's goes, just remember that Ford uses the same parts across most platforms.

You may be surprised how much interchangeability there is between Ford vehicles.

Ill try it when the temps drop a bit thanks. And yes about interchangeable parts thats helped when scouring for parts in the past i was more reffering to wiring locations, for ecample my trans connecter was mounted on the side of the engine not bolted up to the firewall which made it difficult to check the wires without much slack in the harness. Ill try with the oe wire removed, not much to lose at this point. Will be back with results!

 

[primordialpaul]

When you jumped it from the connector at the firewall to the alternator did you unplug the existing wire?

If you have voltage before it goes into the trans harness connector but not after, then you have the same issue I had.

Unplug the green/red wire from the alternator, connect a jumper, check the jumper for voltage, then connect it to the alternator.

That's what worked for me.

As far as the charging system being different between the 5.0 and the 4.0's goes, just remember that Ford uses the same parts across most platforms.

You may be surprised how much interchangeability there is between Ford vehicles.

I had twelve volts at the connector, when plugged in it dropped. I cut the wire between the pcm harness and trans harness (i believe thats what you were saying to do?) And put a jumper from the firewall harness to the alt connector. I read twelve volts with key on and batt light does not come on. But the car just turns over it does not start now. Did i jump it in the wrong place? Edit: i tried it jumped from the other side as well same issue full votage key on car turns over strong doesnt start.

 

[koda2000]

Are you sure you cut the right wire? With the new piece of wire connected to the alternator does the BATT light come on with the key in the ON position? If it's not even coming on you must have cut the wrong wire. Do you know how to do a continuity test on the wire you cut to see if it's the one going to the alternator? Try leaving the new piece of wire in place, reconnect the wire you cut and see if it starts and if the light goes out. if the light goes out when the engine is running the alternator should be charging.

 

[primordialpaul]

Are you sure you cut the right wire? With the new piece of wire connected to the alternator does the BATT light come on with the key in the ON position? If it's not even coming on you must have cut the wrong wire. Do you know how to do a continuity test on the wire you cut to see if it's the one going to the alternator? Try leaving the new piece of wire in place, reconnect the wire you cut and see if it starts and if the light goes out. if the light goes out when the engine is running the alternator should be charging.

Youre right i didnt even notice but no the light doesnt come on at all. Ill hook it up with the new wire pigtailed in and see what it does, im pretty sure it was the right wire though, the other with green and red are more red than green its not too difficult to discern. I may look for the ignition switch diagram to see how i would go about running a wire straight from that if all else fails, i had the lcm on my 03 interceptor fail a few years ago and ran a complete set of new headlights with relays and all to new sockets and that lasted the life of the car, i may be looking to do something similar here if it wont burn anything out in the process.. obviously alternator is not the same as lights but it may be a viable option. If nothing else works.

 

[primordialpaul]

Yeah pigtailing the alt wire into the other reconnected didnt change anything, and even putting all the wires back to stock didnt do anything made sure no fuses were blown, it just wont start now, im all done. This is way worse than i thought it was going to be, so this truck is off to the junkyark. Thanks for giving me your time folks.

 

[Dono]

As I understand it, the bulb in the cluster being burnt out could cause this also. The circuit isn't difficult when looking at the schematics. I struggled once, and it turned out to be the alternator not grounding to the motor. You checked that, so my only other guess is that cluster bulb or bulb connection. Yea, these can be frustrating.

 

[primordialpaul]

As I understand it, the bulb in the cluster being burnt out could cause this also. The circuit isn't difficult when looking at the schematics. I struggled once, and it turned out to be the alternator not grounding to the motor. You checked that, so my only other guess is that cluster bulb or bulb connection. Yea, these can be frustrating.

Well i got a weekk before the junkyard has time to come grab it so i guess ill keep at it til them maybe ill get my answer. I dont know how the connection to the bulb would be bad though, with all the wires back where they came from the bulb still works but now it wont start at all when before the car would start with a charged batt or jumped now it just turns over so i have no idea where to go to now. Fuel pump kicks on all connections are solid i didnt understand why it wouldnt charge before and i dont know why it wont start up now.

 

[koda2000]

Well i got a weekk before the junkyard has time to come grab it so i guess ill keep at it til them maybe ill get my answer. I dont know how the connection to the bulb would be bad though, with all the wires back where they came from the bulb still works but now it wont start at all when before the car would start with a charged batt or jumped now it just turns over so i have no idea where to go to now. Fuel pump kicks on all connections are solid i didnt understand why it wouldnt charge before and i dont know why it wont start up now.

I'm frustrated that I can't witness this problem first hand. I'm pretty sure the fix would be something simple, but blind diagnosis on electrical stuff is nearly impossible. Furthermore I don't understand why the engine wont start now. I suspect when you shorted the GRN/RED bypass wire wire and got a big spark a fuse or link blew. Have you checked the mega fuse at the rear of the power distribution box? Also check continuity at the fusible links. Unfortunately it's possible you may have fried the PCM. I'd check for spark at the spark plugs and current to the fuel injectors to narrow the no-start issue down. I hope you figure it out before the wrecker comes. Good luck.

 

[primordialpaul]

I'm frustrated that I can't witness this problem first hand. I'm pretty sure the fix would be something simple, but blind diagnosis on electrical stuff is nearly impossible. Furthermore I don't understand why the engine wont start now. I suspect when you shorted the GRN/RED bypass wire wire and got a big spark a fuse or link blew. Have you checked the mega fuse at the rear of the power distribution box? Also check continuity at the fusible links. Unfortunately it's possible you may have fried the PCM. I'd check for spark at the spark plugs and current to the fuel injectors to narrow the no-start issue down. I hope you figure it out before the wrecker comes. Good luck.

For continuity im checking for resistance? High resistance means an open circuit? Im trying to get my hands on starting fluid to see if it kicks because it sure doesnt seem to sputter or anything.. such a shame i shouldve had the diagrams in front of me doing this it all could have been avoided. I have fusible links in lieu of the mega fuse ill check for voltage there to start.