Warbirdone

I've been working on my buddy's 05 f150 fx4 5.4l for a few days now. He was having some electrical loss when he would turn on more than one device at a time (headlights/radio at the same time). He took it to a mechanic who told him 4 of his ignition coils were bad and he wanted to change them. Then the car just stalled and died while driving and wouldn't start again. I didn't bother checking it out and just told him get the coils and I'd put it in (he wasn't clear at the time on what the issue actually was, just what he had been told it was). So after I put in the coils and cleaned the ridiculous amount of sand out of his spark plug holes, I determined that while the car would run with another car jumping it, the voltage would quickly drain as soon as it was disconnected....his alternator was bad. I figured the low voltage and power drain was from the alternator on its way out before it completely went out. So we took it out, tested it, it was completely dead, and replaced it. It worked better than it had been in months for about 5 days and suddenly today it stalled twice again. Same power loss when he turned on his radio, or even tapped his brakes, all the lights would dim, the cd changer would reset, and the car would almost stall. There's a strange whirring sound coming from the new alternator and I'm not sure if it's normal noise or not, seems a little loud as we can hear it in the cabin. While driving, the battery voltage meter stayed steady, and as long as the radio was off it would be fine. What are the odds that the new alternator is also bad? And what else could cause a complete power loss to everything even when the battery is fully charged? Could something else like a short somewhere maybe have fried the new alternator? If the alternator is bad, and the batt is charged, could a load like running the car with the lights and the radio on cause it to overpower the battery? It's a new battery so it should be strong enough to run everything for at least a few minutes right? The meter didn't drop on the voltage at all. Suggestions? Also, while working on the truck the first time, when old alternator was installed still, there was a rapid fire clicking coming from behind the back seat, sounded like a relay clicking on and off very quickly. Could that be something related? It stopped as soon as the new alternator was installed. And where the hell are the fuse boxes in this truck?

Code 7

Doesn't your friend have an owners manual for the truck? That's pretty much an imperative. The fuse box is on the R side along side the passengers leg. There's a door that you just give a good yank on and it will come off. There is also a fuse and relay box under the hood on the L side. The relay clicking behind the rear seat is the BSM (body security module) It's what your keyless entry goes through, but quite a few other thing are routed through there also!
By the way, if that mechanic thought that his problem was the ignition coils, I would stay a long way away from him!
As far as whether you can get a bad rebuilt alternator, I'd say your chances are better at getting a bad one than getting a good one. Remember, those things are rebuilt by guys making minimum wage who have NO IDEA how what they're rebuilding even works. I don't ever buy rebuilt starters or especially alternators. Bad right out of the box way to often.
With the battery charged up good, put a volt meter on the 2 battery posts to see what you show at idle. It should be 14.0-14.4V. I suspicion that it is a bad rebuilt alternator and you were just running on the new battery for those few days that there were no problems. Most rebuilt alternators use cheap, no name, foreign parts to rebuild so you can't expect to much out of them. At least get a good rebuilt from Ford or Napa, and even theirs aren't ALWAYS perfect. Don't expect much out of Autozone or some of the others, you're not going to get it.

Warbirdone

Thing is it wasn't a refurb. It was new out of the box from autozone. Unless they're all refurbs ? And the first time you could watch the voltage drop on the dash. Now it stays put. No problems starting the car after it stalls either.

Code 7

Warbirdone- Not sure exactly what has gone on between post 1 and post 3. Do you have another new alt. on now?
??????
No, if it was supposed to be new I'm sure it was, but there are bad new parts as well. You may not have a choice of parts stores in your area but if you do, my suggestion is give Autozone a WIDE birth! In other words stay away from them, definitely on REBUILT parts. They make China look good. (sounds like even on their new parts) I seldom EVER go to Autozone and NEVER for rebuilt.
Just put a DVM across the - and + posts on the battery and you can tell exactly what the alternator is doing. I don't trust the dash gauges on the newer Fords (and probably a lot of other newer cars and trucks also), you used to have idiot lights, now you have idiot gauges. FEEL GOOD gauges that make you think you have real, reliable gauges when it's a farce. Ever wonder why your oil pressure gauge shows about center all the time? So close to a farce that they're joined at the hips.

jonquil

With the engine running, pull the cover off the fuse panel in the passenger side kick panel. Did the problem manifest? Next, push lightly on the fuse box itself. Any strange things happen? Also, tug lightly on the wiring harness going into the fuse panel. Try this with the radio and other accessories on and carefully watch for signs of the problem rearing its ugly head at the precise moment you tug or push. If it shows up, you'll have to replace that fuse panel. I did.

I learned the hard way that some of the 04 - 06 models have a problem with that fuse panel. Depending on which of the printed circuit boards is causing the problem (there's 4 or 5 of them), anything that is fed thru that panel can act crazy as hell. What happens is that one of the soldered circuits on the back side of one of those printed circuit boards gets a hair line crack in it and whatever it feeds goes crazy, at times. I learned mine was that way by accident. Check it out. It's free, easy and quick.

Good luck.

Mod (Ret.)

Circuit board on a fuse panel??? My 05 does not have this. The wiring looms to the various electrical circuits all terminate to the fuse box to their assigned fuse(s). No circuit board is involved at the fuse box itself. At least not on my 05.

As to alternators, I agree that buying a new or rebuilt one from the autoparts store is a huge crapshoot at best. Sometimes you're lucky and you'll get one that will last for a year or two. Here's where I go the route of an OEM unit from the dealership parts counter. You'll pay a whole lot more, but it will last much longer than the cheaper ones at the auto store.

Here's a tip: go to EBAY motors, select parts and accessories, and search for an alternator, starter, or what have you. The salvage yards sell them all day long here, and for cheap. They are OEM off of wrecked/totalled trucks, and they post the mileage of the vehicle they come off of. I bought a spare alternator and starter for my 05 4.2 V6. Got them both for under a hundred bucks, off of a truck with less than 36K on it's odometer. I had both tested, and are in great operating order.

You get OEM replacement for less than the price of the aftermarket cheap stuff.

Code 7

.

. Bucko- Everything is bigger in Texas..... except the used parts prices! That is a REALLY good price for what you described. Vehicle prices are highly competitive in Cal., but not so much the used parts prices, not for what you got anyway.