My 2001 PSD 7.3 was throwing a couple of codes last 12 months 208,532 miles
Old code was glow plug 7, latest code was glow plug 2.
Had dealer change out all 8 , and wiring harnesses.

After picking up truck, I had it on driveway for about 4 hours while I reloaded ALL of my work gear.
So all the courtesy lights were on, total of about 8 bulbs?

When I went to start it, dash made noise like relays drawing, clicking, etc. About three attempts of that. Then truck fired up.
So I took my new COSTCO bought Duracell 4 amp battery charger / Maintainer. I charged passenger side battery about 5 hours, then switched it to drivers battery for the rest of the night. ( about another 5 hours)
Truck fired up next day. I watched stock voltage gauge while glow plugs engaged.
Everything seemed good for about 4- 5 days ( 500 miles)
Then I noticed red factory dash battery idiot light flashing. Then staying on. I am wondering if the 4 amp battery charger / maintainer screwed up my regulator?, alternator?, or batteries. I did not disconnect any cable while doing the charging process.
So I started watching stock voltage gauge ever since, and I researched the alternator recommended on this site. The 6G American and Canadian parts only. 140 amp. https://alternatorparts.com/6g-serie...lternator.html

I did not buy alternator yet, because I wanted to take my Harbor Freight battery tester/ load tester device out of its brand new box.
So I tested it last night. Batteries are only putting out about 12 - 12.5 volts at idle.
I think I am going to buy the alternator, but any thoughts from the informed peeps on this site?

Thank you for your time and effort spent on my behalf!

 

That definitely sounds low. But alternator output always needs testing under load, while energized. Turn on all the headlights and accessories and heater fan blower, and spool up the idle RPM high to spin the alternator fast and hold it there. Typical #s 13.8 - 14.3

I doubt the charger hurt anything.

 

There is a plug on the back of the alternator next to the big B+ wire. Check those wires for chaffing, breakage inside the insulation or broken at the plug. Also check for continuity and short to ground. It sounds like the alternator is not getting the signal to activate from the computer. If the truck was just worked on, it is possible someone broke one of the two wires going to/from that plug. It could also be the plug is not seated all the way.

 

Your regulator (which is inside the alternator) may be acting up. It has a separate wire running to it and if shorts out (like mine did), then the battery dash light will come on intermittently at first, then it will stay on solid when it really pooches. In my signature below, click on the "Bad Regulator Wire" link to read my experience. Maybe the same thing is happening to you. Keep us posted.

 

Yes, I agree with the wiring, regulator plug hypothesis, but was unsure how to proceed exactly.

 

Push on the plug on the alternator if you hear a click it wasn’t completely seated. If there’s no cluck, Unplug the alternator inspect both the alternator and plug sides for signs of damage. Look at the wires from the plug back into the wiring loom. Check fuse 27(IIRC) under the dash to see if it’s blown. Then do 2 checks of the alternator for voltage at the alternator after the GPR has shut off. 1) everything off in cab you should see high 13’s to low 14V. 2) turn everything on in the cab, you should see voltage climb as the regulator commands for more voltage. If you have a chip with a high idle setting that works great.

 

As stated in my link, the orange/light blue wire was the one that was shorted somewhere in my wiring harness. I wish these jamokes had circuit tested this wire near the beginning of the troubleshooting process instead of simply mounting and dismounting three different alternators to try to solve the problem.

 

It would be nearly impossible to hurt anything with your 4amp charger. Also, since the batteries are connected together there is no reason to switch the charger between batteries. No matter which one you connect it to they will both get an equal charge, assuming the wiring/connections are good.

Check the little plug as suggested, if that's good check the voltage at the big wire above it and the voltage at the battery with the engine running and some load on like the headlights, they should be really close to the same. If not then there's an issue somewhere between that connection at the alternator and the battery. Also, after a cold start the glow plugs can run for up to 2 minutes and during this time your battery voltage will be quite low and because it's a big load you'll see more voltage difference between the alternator output wire and battery. Once they turn off the battery voltage will start to rise. With no load and charged batteries you should have around 14v. at the batteries at idle. If all your connections are good you have a bad alternator.

I went to my local rebuilder and swapped my stock small case for the large case alternator used on the 6.0. I think it was $120. Voltage while the GPs are on and recovery after they shut off are night & day, but my alternator already had a bit of a problem. Not enough to trigger the light, but it was definitely faulty. Everyone who's done that upgrade has been happy. I think the standard for that alternator 140a and it's plenty for most people while not being so much that it'll necessitate modding the wiring.

 

I think it is not charging, because on Friday after a few short trips, gauge on dash was down to less than 8 volts, but I was able to quickly start motor befor glow plugs drew down voltage too much. Then voltage gauge shows in middle, but not higher than middle,

I did inspect plug and some of the wiring right near back of alternator, but not full inspection.
Ill check fuse 27.

 

Truck would not start yesterday after driving in rain with headlights on.
Inspected plug and wiring again on top of alternator.
Been trickle charging passenger battery past 18 hours
Alternator biz ( the one mentioned on this site) is closed today for Christmas

 

Check continuity (verify good connection/no broken wires) between alternator and computer, and then alternator and dash (the two wires in that plug). Quick and easy to do if you have diagrams.

 

I do not have any diagrams

 

There is a strong possibility what you are looking for is in the 7.3L PSD Tech Folder

 

Ok, I received my new 140A alternator from one of sources recommend on this site.
So I decided to swap the serpentine belt and the longer upper radiator hose.
So I tried to put belt on first without upper radiator hose or alternator in the way.
I failed miserably???
What should I do first??

Belt? hose? alternator?
I really could use any knowledgeable advice about the serpentine belt.

Thank you all in advance

 

Ok Project almost done.
Talked to a Ford mechanic. He said put hose on, alternator on, then belt.
I watched many you tube videos, but they skipped the actual belt install. Finally found a 19 minute video, 12 minutes in the guy showed how to install belt. I will post link So I went to Napa and bought a black 4 ga 35" cable ( 781112) and installed from ground bolt on back of Quick Start 140 amp alternator to drivers side negative battery post cable.

Also from Napa bought a red 4 ga 55" cable ( 781143) and installed on hot post of alternator, (along with stock hot cable ), I ran that cable over to passenger side fender well where starter solenoid is. The Quick start hot post diameter was larger than my stock alternator, so I had to drill out ring terminal. That was scary as drill spun wiring harness a few times.
The Napa cables have large end on one side, so had to modify hot post insulation, maybe to my future detriment? Used large heat shrink. So cables may not be ideal but they work.

OK so I thought about it some more. The Napa cables are not ideal. The ends may need to be modified, so if you can buy similar with the same ring terminal end on all 4 ends you would be better off!