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What is this thing???


C-Bear

Member
Joined
May 2, 2012
Messages
10
Vehicle Year
1994
Transmission
Automatic
Hey everyone, I've got a 98' ranger that's having a charging problem. I think I've narrowed it down to being a short or something on the light green and red wire that runs from the alternator to the battery light symbol on the dash. I've also heard that it "turns on" the alternator. I've been tracing that wire and see that it runs from the alternator, to the pcm, and then from the pcm to the clip that plugs into the dash for the battery light. However while searching down around under the steering wheel; theirs a light green and red wire that goes to this light post and is attached via a clip.

It sits right behind the emergency brake and has a little spring loaded thing on it, but I can't figure out what any of its for, theirs no other wires attached to it.

I'll try my best to explain it exactly, I can't figure out this uploading pictures thing.

It's a white plastic clip that's attached with a gold screw, its got a little spring loaded pin that sits on top and when you push it down it just comes out of the bottom, the wire is attached right behind it and it is connected with a small clip.
It is really small and literally right behind the emergency brake, kinda right in the corner.

Please let me know!
 
I'm pretty sure that's the parking brake switch, it should mount to the cab wall behind the brake lever. It turns on the brake warning lamp when the parking brake is engaged, so you don't forget and try and drive off before releasing it. That wire runs to one side of the switch, and the other side is hooked to ground by a screw into the cab wall.

They used more or less the same system in the 1st gen Rangers (if not more); the one in my '88 was cracked and I had to repair it.

It shouldn't have anything to do with your alternator or battery problem, unless you have catastrophic wiring problems.
 
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I can't find a charging system diagram for a 1998 Ranger online, and my Chilton manual stops at that year. I'm sure it's a different system, but I had an issue with the "off/on switch" on my alternator fairly recently, it seems that the green/red striped wire on my 1994 4.0 grounded out somewhere between the instrument cluster and the alternator, I just snipped the wire at the cluster and replaced the whole strand. Again I'm not sure how similar the two systems are but I figured it'd be worth sharing.

Here's a link to my thread: Charging system problems
 
Green/red wire goes from alternator to the dash board battery light, should not connect to anything else.

Yes, that wire is the ON/OFF for the alternator.
When you turn the key on that wire sends 12volts to the alternator, thru the battery light, when the alternator is not turning it has 0volts at the alternator end of the wire and when you hook up a light bulb to 12v and to 0volts(ground) the bulb lights up.
So when you turn on the key the battery light comes on.
When you start the engine, the alternator is now generating 14volts, so both wires at the battery light have 14volts, and bulb is off.

If you unplug the 3 wire connector on alternator and turn on the key battery light should stay off, no 0volts, if it is on then yes you have a short, if you hook the 3 wire connector back up battery light should come on

1998 charging diagram here:
 

Attachments

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You can register at autozone for a free account, and then they'll let you access service manual info for any vehicle in their database. That's where I find a lot of wiring diagrams for various years.
 

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