Hello, all, I need to first apologize for just throwing this out here; I had very limited luck in searching about my problem because I'm not sure how to best word the searches. Second, I need to apologize because I am posting this to three forums for Fords because I'm not sure which will have the most active users.

On a 2010 F350 Diesel I'm helping a guy with: batteries found dead one day. One tested bad. Guy jump started truck (with 12V) and drove to store to get batteries and then changed them. After changing batteries, however, the truck will not start. This is the point I got called in.

The batteries are connected correctly (parallel). The ground wires to each battery are connected to the chassis and verified with a digital multimeter set for continuity checking. What I call the PDM (power distribution module), fuse block, under the hood supplies several circuits in the cab. The PDM has voltage from the batteries, verified with the meter.

This is where it gets weird: the 12V outlet at the dash near the steering wheel has power, the passenger-side electric seat works. However, turning the key to the run or start position gets no response, the same as the horn, hazard flashers, brake lights, driver's seat, and instrument cluster. Just dead. I removed the fuse from the passenger-side electric seat and switched it with the one for the driver's side. The passenger-side seat continues to move/function, and the driver's seat continues to not work. I found 12V at the fuse connector for the driver's side seat...but it still doesn't work.

This confuses me; some circuits from the PDM in the engine compartment work, and some do not. I'm at the point where I think it can only be a ground wire which exists under the dash and only is connected to some circuits, meaning power from the batteries for other in-cabin devices can flow across some other ground wire exclusively for them.

I'd love to have some input, please. Also, if someone can tell me where a community ground wire for the listed affected circuits is under the dash I'd appreciate it so I can check it.

Thank you.

--HC

 

Problem is what caused the dead battery in the first place.that probably is the start of the problem. Look at the connections at the fuse block. Make sure that the wires are tight at the starter. Look for fuseable links in the battery power wire.

 

Load test both new batteries. Do a voltage drop test on all the secondary (large) wires to the starter. My moneys on one of the grounds and or the starter is bad. Bench test the starter and its solenoid.
How many miles on this 1 ton? Is it rusty?

 

Thank you for your reply.

Yes, what caused the original dead battery situation is a good question. Unfortunately, I cannot answer that other than to say that the guy found that one battery would take and maintain a charge and load test okay, and one did not. I presume that one battery, both of them 5 years old at that time, went bad inside with a bad cell, and started discharging, taking the good one down with it.

The connectors at the fuse block up top seem okay. If you mean the connectors at the bottom, I was unable to release and then move the PDC/PDM/fuse block far enough to view the bottom.

If a "fusible link" is inline with the cable from the battery to the fuseblock (PDM/PDC) under the hood, then I'd have to say it was in good shape; I have voltage at PDC under the hood and then at some of the supplied circuits. I only saw one cable from the positive terminal of the driver's-side battery to the PDC under the hood so I believe that electrical connection from the battery to the PDC must be intact. I'm not preaching, just saying what I think with what I know at this point. Feel free to correct me if I'm wrong.

And, I'm not sure what a fusible link looks like, I'm sorry. I'll look that up online.

Thank you for your time.

--HC

 

Thank you for your reply. Please forgive me, I don't intend to be a jerk, but I feel that a detail was misunderstood. The vehicle doesn't fail to start because the starter doesn't get enough power; the vehicle fails to even light up the instrument cluster when the key is turned on, not even in the Start position. No solenoid click, no nothing. Headlights, horn, et cetera, do not work. The power seat on the passenger side works fine, supplied from the same PDC/PDM as the driver's side, and, I believe, the ignition circuits, and that seat draws some power, based on it's fuse size of 20A...or was that 30A? So, I'm thinking that the power from the batteries is good.

The truck has about 60k on it which is piddly for a 2010, I'd say. My 2011 F150 has over 90k on it, bought new, so all miles by myself. The connectors at the battery are *clean*. The guy has taken care of them and they were coated in a reddish coating to prevent corrosion and look fantastic.

Thanks again for your time.

--HC

 

I called the guy after the initial responses across my posts to tell him I'd not forgotten him. He told me he just got it fixed. Another guy he knew came to look at it and knew what was going on.

On the passenger-side battery, he tells me, there is supposed to be 3 wires to the positive terminal. However, there were only 2. The owner who changed the batteries apparently dropped one of the wires and didn't remember that it had been there. The wire is, reportedly, very short, and was not visible once it had fallen down. Upon connecting this 3rd wire, everything works.

Now, WTF?! Why does the passenger-side power seat work but not the driver's-side seat? Both fused through the same PDC supplied, apparently, by one cable from the driver's-side battery. I don't know. But I do know the owner tells me that the truck works now because one other cable to the passenger-side battery is connected. Engineers.

--HC

 

I don't believe an incorrectly assembled truck is one of their test cases for the seats. Maybe for 2016?

 

I'd love to cuss Ford in general; I've got a 2011 F150 Ecobomb and it's given me some troubles now and then, but....these things are so complicated and the redesign each few years is, seemingly, a whole new truck, no matter which manufacturer made it. It's amazing they get the things designed, built, and documented.

That said, I'll get vis-a-vis with the truck later today or tomorrow and verify that the driver's-side power seat now works...maybe it wasn't working all along and I've got erroneous feedback from the vehicle. But if it works it'll be about the most bizarre electrical setup I've seen...but I'm not an expert.

--HC

 

Redesigns...not...Except they forgot to pull out the dam foam (sponge) in the inner rear wheel well housings that causes rust through in 5 years!!! (thats been there at least back to 99)... AND to add a little more XG-8 grease to the slip splines on all these "redesigns"
Lets hope the death wobble and rotted/broken exhaust manifolds n studs have met their fate on the drafting & R&D tables????