Driving my '00 4.0L ranger yesterday, the charging light started flickering, and power accessories started running slow (It was raining and the wipers at normal speed were taking 3-4 seconds for a full cycle.) Power windows and locks stopped working. Once I stopped and turned the engine off, it wouldn't crank at all - not even a relay clicking noise.

It had the original battery in it, and I'd been warned by a few mechanics to replace it due to it's age, but normally the truck starts so easily, you only have to quickly bump the starter and it's running. Anyhow, I decided whatthehell, try a new battery, it's due anyway. I stuck a new one in, measured the voltage at 12.5, started the engine, measured the battery voltage, and it was 12.1, and slowly dropping to 11.9 after maybe 10 seconds. I killed the engine and disconnected the battery. Clearly, not charging.

So now, I'd like to check the wiring before I spend any more money. The manual talks about a fusible link in the black/orange wire from the alternator to the battery, but everything is wrapped in tape, and plastic wire wrap. Does anyone have an idea where the fusible link is? Or do I just have to start un-wrapping the harness until I find it?

 

Sounds like an alternator problem to me.

 

Alternator.

I'd suggest replacing it before you wreck the new battery. It's possible that you've already wrecked the new battery- a bad alternator on a ford will do that quick.

On a very related note, has anyone else noted that a bad battery will take out an alternator, and a bad alternator will take out a battery?

I had to do that dance a few times with my '89 Crown Vic before I got it straightened out. When I had electrical problems on the ranger, I replaced them both at the same time and haven't had an electrical problem since. (I did establish that the alternator was shot, but I forget exactly how.)

I was somewhat dissapointed that the voltage gauge on my dashboard didn't help. It read just slightly below the middle (normal) until the battery and alternator were completely shot.

It would have been nice if the gauge had been set up to clue you in on a degraded but not yet fatal condition.

 

A bad battery will kill an Alternator makes it charge to hard to long. A bad alternator can kill a battery two ways if it is overcharging it will cook a battery and if it is not charging then the battery will be heavily discharged. Todays batteries will only stand being drained to nothing about three times then they are toast. I see a lot of late model Ford Alternators that have worn out brushes and ruined slip rings on the rotor which is what our symptoms would indicate. But this usually doesn't happen until the mileage is pretty high.

 

Not sure if this is applicable, but that wire with the link runs from the alternator to the solenoid on my '94 rice ranger (mazda). The link itself is only a few inches from where it connects up to the solenoid (which is mounted on the inside fender on mine). When mine blew, the alternator quit putting out the juice. After I replaced the link, I was up and running again.

If you see that colored wire on the alternator and on the solenoid on your truck, check to see if there is continuity between both ends before going further. Make sure you disconnect both ends of the wire (and a battery cable for that matter) before you do that, too.

If there's no continuity, start looking for the link, which usually looks like a wire that has a 1/2" or so piece of vacuum tubing slid over the top of it. Visibly, a blown link looks no different good one, so you know.

Good luck and keep me updated.

 

Double posted by accident here. Maybe someone could delete this one for me.

 

What to look for when a fusible link "blows". The insulation might have a hole in it, the "link" will feel soft and you could be able to pull it sort of like a piece of rubber. It will stretch fairly easily.

 

The wiring was fine. I checked w/ a voltmeter, and had power at the alternator terminals. So I went and got an alternator from ford. The swap was easy with the exception of getting the pulley off the old alternator. I tried using a strap wrench on the pulley, and a socket on the nut, but only succeeded in breaking the strap wrench. After that I decided screw it, they'll take the core back no matter how badly it's damaged, so I jammed a screwdriver into one of the vent holes to stop the rotor from turning. It still took all my weight w/ both hands on the wrench to break the nut free, and I ended up slamming my elbow into the fender.

My question now is, how tight should the pulley nut be, and how to you stop the shaft from turning while you crank down on the nut?

 

To hold the shaft while loosening or tightening it use an allen wrench in the center of the shaft.

 

There is a hole in the end of the shaft, but it's not hex sided or square or anything. Just a round hole. The largest allen wrench I could fit into it was 3/32, and even if it was gripping, there's no way I could get much torque with that. And there's no access to the shaft from the back of the alternator.

I tightened the nut as much as I could by pressing the pulley onto the shaft by hand and then holding the pulley while tightening the nut, but after a certain torque, the shaft starts spinning inside the pulley. I'm wondering what the torque should be. Anyone have the specs?

 

94 ranger 4.0 battery fully charged turn the key nothing happens,tryed turning on head lights no lights put on charger i get light till i shut off the charger. HELP please.

 

Pulley nut torque is 80 ft/lbs.

 

It would be better to post this in a new post rather than attaching it to the end of an old, dead post.

On that note, have you taken the battery in someplace to have it load-tested? It sounds to me like it has a dead cell. A meter can tell you that the battery is fully charged, but when you put a load on it, you can get a completely different result.