'08 F350 Electrical Followup

Steve@Advance

Well-known Member
About 2 months back, I posted a question about an '08 F350 with an electrical problem, the aux power would not go off after the door was opened. I spent a couple days dismantling the dash, searching for mystery modules, searching forums, searching YouTube, the usual stuff...

Finally gave up, decided it was over my head, didn't have the computer equipment to search the electrical system. Told the owner (my boss) he would be better off to take it to the dealer, which he readily agreed.

Meanwhile, over the next few days, the problems began to increase. The wipers came on by themselves. Pulled the fuse to stop them, put the fuse back in, wouldn't work at all. The trailer brakes would only partially apply. Seems there was something else, can't remember now..

So he takes it to the local dealer that has done work for him before. It stays there for a week, calls them. "Yes we looked at it, but it has electrical problems, nothing we can really do... But we have a new truck you might be interested in!" Yep, that's what they told him!!!

Takes it to another dealer. They look at it, install 2 new batteries. (The batteries in it were 3 months old, run down from the electric drain.) They replaced the aux relay that was hot. (It was hot because it stayed on 24-7.) Pronounced it fixed, went to get it, batteries dead! No wipers. Leave it for further diagnosis...

Called a week later... "We think we found the problem. An "instrument cluster module". Have to order it, be in in a week."

Called a week later... "Well, that fixed some of the problems, but..."

Called a week later... "We think the module they sent was bad, ordered another one..."

Called a week later... "Well, we have another truck just like it on the used lot. We've started switching parts off it trying to find the trouble..."

Called a week later... "The tech from the factory is on his way..."

Finally got it back. So far so good. $2400.00

Now I don't feel so bad for giving up on it! LOL
 
Intermittent electrical problems are the worst. How much of that was the actual repair and how much was just paying for guesswork?
 
It wasn't intermittent, the aux relay stayed in no matter what. That was my goal, to unplug a module and have the relay drop out. Never could find where it was getting power.

The original estimate was $2100. They lost on this one, no telling how many hours of guessing they invested!
 
I would have asked what the actual problem was since it seemed to take a factory person to figure it out for them.
 
Your point about the relay staying on is a give away. If I was a betting man (who am I kidding, I'll bet on anything) I would say the relay was a ground out (to activate) type and if there wasn't a short to ground in that wire (chaffed insulation, etc.) the main computer (engine control module or body control module, whatever they have to control it) is probably bad.
 
It must be great to be a mechanic wherever you are. In California, it is illegal to charge for an ineffective repair. We get to pay for and keep all those parts that didnt fix it.
 
I wanted to know what the final fix was. But I wasn't there when it was picked up, so will never know... Doubtful they would have told anyway, especially if it was something really simple!
 
I'm in Texas. Come to think of it... I remember many years ago there was a law passed that the shop had to save and provide the old parts at the customers request. Have never heard of it being enforced, would be difficult with rebuilt exchange. Impossible to prove the parts came off that vehicle.
 
From what I hear it is caused by a leak in the windshield and water getting into the module in the dash-dealers should be aware of this.
 
The electrical systems on all of this newer equipment are a total nightmare when they acted up. I can easily see where it cost a lot of money to repair some of this stuff. There are many problems that the "computers" will NOT diagnose. This is really true if it is a wiring circuit issue or a ground issue. A back feeding ground can cause all kinds of weird things to happen.

It sounds like they estimated the repair at $2100 and the final was $2400. They really where not far off. Now as to what they actually found wrong??? They may have came out in the black on this repair but I would not be surprised if they lost MONEY on the repair. Things like this tie up a good mechanic for hours/days when they could be earning much more doing other repairs.

All of the good repair shops around here are weeks/months behind in work needing to be done. This includes many of the dealerships as well.

Truthfully most of the electrical systems on this modern equipment is so far above the average mechanic's ability it is not funny. I darn well am including myself in this as well. Much of this new stuff will be unrepairable in the new future. It is so complicated that when it messes up there will be NO ONE that can repair it.
 
You can't fix'em all sometimes you make more shipping it and work on something you can make money at :!: Even at that price I bet they lost there arse on it...

I am about to age out and turn it over to the next generation...
 
"Much of this new stuff will be unrepairable in the new future"

That's the truth! The future is now... No reason to make something this complicated other than to force you back to the dealership!
 
Had a F150 do the same thing. It was the GEM module as mentioned above. You can't just replace it with another one, the new one HAS to be the SAME number and sometimes even programmed to operate correctly. This module controls the interior lights, wipers, windows, security, and many others things and options the vehicle might have. Ford had a bad problem this the windshield leaking and water soaking this module and that is usually what causes them to go bad. It is located above the fuse panel under the dash and can be difficult to replace.
 
Just a few points of information here, Steve.
As a retired Ford technician, former ASE certified master auto and heavy duty truck technician, I have a bit to say about this.
First, as you have seen, there are no short answers - especially when it comes to the electronics.
Second, Ford publishes some REALLY GOOD diagnostic books. Their EVTM manual is a "must have" if you are working on an electrical system. It takes all of the guesswork out of where, why, and how modules/relays are powered. Includes plain and readable schematics, color codes of wires, location of ever module, relay, ground, fuse, and whatever else you need to know. I have these manuals for every vehicle I own.
Last, but not least, folks that believe that the computers will tell you whatever is wrong, and you just replace that part........ NOT going to happen. Ever. Computers can be a very helpful diagnostic tool, but there is still no substitute for the eyes, ears, and hands of an experienced mechanic.
 

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