Solved Charging system wiring questions.

[Road1]

2017 FPIU, 3.7 engine.

A couple of days ago (after cold soaking down into the 10F range), I got an intermitted popup to check the charging system NOW. I was seeing a proper charge on the VOM, but the serpentine belt was showing a puff-out of a couple of fibers, so I replaced it.

I'm still seeing the popup, and now not seeing any charge on the VOM. I charged the battery (12.6VDC) and checked with FORScan, getting P0625:00 and P0658:00.

I have the troubleshooting list and planning to dig into it later today or tomorrow (yep . . .my FPIU is a true Thanksgiving turkey!).

QUESTION 1: I'm assuming that the ring around the negative battery cables is the battery monitor. Am I correct in thinking that the plug on the alternator is only wired to the plug on the battery monitor? That plug is easier to get to than the one on the alternator.

QUESTION 2: Is there a PDF of the schematic for the 2017 FPIU 3.7 online somewhere?

Thanks!

 

[BrooklynBay]

Did you check the high current fuse?

 

[Road1]

Where is the high current fuse?

 

[BrooklynBay]

Check the owner's manual.

 

[Road1]

Check the owner's manual.

Oh, yeah, like I got an owner's manual!

 

[ProjectSHO89]

Am I correct in thinking that the plug on the alternator is only wired to the plug on the battery monitor?

No. Refer to schematic below.

Questions:
Q1. Are you certain about that "P0658" DTC? Perhaps a P065B instead?
Q2. Do you have a good understanding of how this PCM-controlled charging system works?
Q3. Do you have the factory diagnostic procedure?

Oh, yeah, like I got an owner's manual!

Owner's manuals are downloadable at Ford's website.

Here is the schematic for the '17 Explorer's charging circuit.

 

[Road1]

A1. Yes, I read it wrong the first time.
A2. I think so. Unlike older alternators, this on only puts out current if told to by the PCM.
A3. Yes, I just found that. I also got the online owner's manual. Is the tech manual online somewhere?

I am NOT seeing a "high current fuse" mentioned in the owner's manual.

I discovered one problem (dunno if I caused it) -- while trying to remove the C102A plug in the back of the alternator, I found a wire hardened and broken. Replacement plug on the way. I also found that the insulation on the 3 wires had been warm enough to soften and stick together at some time in the past.

Apparently this plug and wires are a common failure point. I'll get the new one in and then go through the rest of the troubleshooting.

HINT for anyone reading this in the future, the retainer for this plug is on the side toward the center of the alternator, and is easily released by putting a small screwdriver into the opening and gently working it. Take a look at the picture for Ford part 1U2Z-14S411-TA to see what I'm talking about. The one I ordered was about $18 from Amazon.

 

[ProjectSHO89]

Yeah, I'd repair that pigtail first and then see what happens.

The two high-current fuses, F101 & F102 are on the underside of the battery junction box. They are not considered to be owner-replaceable so are not in the owner's manual.

Good luck!

 

[Road1]

Yeah, I'd repair that pigtail first and then see what happens.

The two high-current fuses, F101 & F102 are on the underside of the battery junction box. They are not considered to be owner-replaceable so are not in the owner's manual.

Good luck!

The UNDERSIDE? Another one of Ford's "better ideas"?

UPDATE EDIT: The fuse is at the FRONT of the junction box. See the two wires connected with nuts? The right side is the lead to the alternator (325A). If the VOM shows battery voltage, the fusible link is good. No voltage, no good. Replace by raising the junction box, disconnect BOTH of those leads under the nuts and BOTH of the lugs underneath. The fusible link is ganged with the 125A/100A link that goes to the other lead, and they come out through the top.

This is also a good place to disconnect the alternator output for testing.

The BAD news is that the ganged fusible link seems to be made of unobtanium. The GOOD news is that a 325A fusible link is a 325A fusible link, so a substitute should be available. Otherwise, try wrecking yards.

I'm also having trouble finding the Lester numbers for the alternator, in case I need to rebuild it. Anyone know this?

 

[ProjectSHO89]

Can you post a photo of what you described? I was going off the diagrams in the service docs. My '15 has the prior version layout.

Am I to understand that yours were open-circuited or were you simply describing "hot to check" (which is correct)?

 

[peterk9]

Oh, yeah, like I got an owner's manual!

Here ya go; https://www.ford.com/support/vehicle/police-interceptor-utility/2017/owner-manuals/

Peter

 

[Road1]

I have a 2017. The fusible links are at the front of the box, with the two big leads connected with nuts.

The one to the right in this pic is C102B, the hot lead from the alternator. Checking with a VOM between this lead and ground should show battery voltage.

 

[Road1]

Here ya go; https://www.ford.com/support/vehicle/police-interceptor-utility/2017/owner-manuals/

Peter

Thank you!

I don't suppose the workshop manual is online somewhere?

 

[peterk9]

Thank you!

I don't suppose the workshop manual is online somewhere?

I've never actually looked for it so I don't really know. If it is, it likely isn't free.

Peter

 

[ProjectSHO89]

It's not online for free except for excerpts that folks post. I do have a copy available to do that, if needed.

If you want to own your own copy at a reasonable price, it's usually possible to purchase a used/expired dealer DVD from ebay. It's fairly straight forward to make them work on a Windows machine. Otherwise, short term access to Ford's data can be rented from www.motorcraftservice.com (under Service Info) starting at $21.95 for 72 hours of access.

 

[Road1]

Thanks! I'll hunt around.

 

[Road1]

I'm seeing standard Explorer manuals -- is there a special one for the FPIU, or is the Upfitter's Manual all there is specific to the copmobiles?

 

[Road1]

FOLLOW-UP:

I replaced plug C102A (Ford part 1U2Z-14S411-TA), and that seems to have fixed it. Not declaring victory until I get 100 miles without failure.

The generic plug cost about $20 (including shipping) (as opposed to $70 for the Motorcraft part). If I had had to take the alternator off, I would have simply soldered bullet connectors to the pins and waterproofed with RTV (if you do this, remember that Pin 3 is incoming B+, so make sure to protect the wire end from shorting).

 

[peterk9]

That appears to be a good price compared to sites I usually check out.
Original Wire Assembly 1U2Z-14S411-TA | Levittown Ford Parts (site vendor offering members a discount)

Wire Assembly 1U2Z-14S411-TA | TascaParts.com

1U2Z-14S411-TA - Wire Assembly

www.tascaparts.com

It's beyond me why people even look to order from Ford parts as they are always the highest in costs.

Peter

 

[Road1]

Well, nuts.

The problem remains. Looks like time to start the diagnostics from scratch and go all the way through.

It would simply things if I could find a tester that would plug into the control jack (C102A) on the alternator.

With the plug from the PCM disconnected, should I see output from the B+ stud?