Hi All,

I guess I'm new, sorta. I was active in the F-250 forums a couple years ago. Sold that one, now in a Ranger. Thus endeth the bio.

The Problem: Jumped in to make a run to town tonite and made it about 1/4 mi. before I started noticing major low electrical power stuff; dim headlights, stereo stuttering, misfires, etc. In-dash battery indicator/meter was reporting wayyyy left of center at about 10-11V (standard hokey 8-18V Ford meter). Shut off everything but my low-beams and limped home.

Charged battery, threw it back in, and at idle checked current at alternator output w/ DC-amps inductive calipers: zero current. Loaded up system to try to force a field voltage from regulator: radio, hi-beams, AC, dome lights, etc. You could almost hear the battery draining away.... This produced no change, so I shut everything down (except the engine) before I drained my battery completely, and while I was standing there looking and feeling intelligent, trying to figure out what to do next, the idle rpm dropped precipitously for just like 2 seconds, recovered, then the alternator started humpin' out the amps: roughly 30A @ about 14-15V (I still had my calipers around the alternator output and therefore immediately saw the jump). Then after a minute or so it stabilized to 13-15A. Checked the in-dash meter and it too had stabilized at about 13-14V. {It should be noted here that the history on my particular dash guage has always read dead in the middle between 8V and 18V, needle pointing straight down, always, never changed ever. I don't place a lot of stock in dash cluster guages, but the consistency is what I wanted to show.}

The condition stayed stable for about 30 minutes, and may well have held all night, but when my guages showed about 10-11A at my calipers and 13-14V on the in-dash, normal nighttime readings for my truck, I shut 'er down and restarted the engine to see if the situation would change. It did: same as before - zero current from charging system. Went thru the same steps of loading, unloading, etc., but no-go. Couldn't get any more rise outa my alternator.

Checked most all the dipstick stuff: connectors, grounds, frayed/worn wires, rapped on relays, jiggled wiring harnesses, etc.

Any help would be appreciated. I could especially use a pin-out on the alternator connector if anyone knows it. Even if I can't get the whole pin-out, maybe someone at least knows which pin is the field voltage from the regulator? I'd hate to replace the whole alt./reg. assembly if it's just my regulator, ya' know?

Thanx in advance! Here's my vitals:

1994 Ford Ranger XLT-Lariat
4-speed auto
3.0 Liter V6
Seq.-MP/EFI
Odo: 117k

 

might be the altenator plug. known to go bad.