I have a '94 Ranger 2.3 with standard transmission. It's a pretty basic little truck and like it, especially when it runs. I'm having some problems with the alternator right now, and I'm running out of things to check. I replaced the speedometer cable just prior. The battery is good, the terminals are clean, the fuse is not damaged. In checking and rechecking, I see there is no voltage going to the alternator from the instrument cluster with the key on. There is, however, continuity between that wire at the harness and the alternator. So...I'm thinking I damaged the instrument cluster when I took it out. I have checked for continuity on the circuit board on back of the cluster and can't find the damage. Still, I can't think of any other reason why the alternator suddenly wouldn't charge. A used instrument cluster is about $160. It's a big investment for me. and I'm wondering if anyone can suggest any other checks I can make before I make that purchase.
Much appreciated.

 

Welcome to the forum

1994 charging system diagram below

The green/red wire at the alternator is the ON/OFF switch for alternator, it gets 12v with key on.........from the Battery Light in the cluster, there is a by-pass resistor in case bulb burns out(shown in diagram)

An alternator can not generate voltage on its own, it must have "startup voltage" thats what the 12v from Battery Light circuit is for
The 12v from ignition switch runs to Battery Light Bulb, then thru the bulb to the alternator, the alternator at this time is "like a ground" so Battery Light comes on
When alternator starts to spin the 12v from bulb is used to charge the rotor and alternator starts to generate voltage
Once alternator is up to speed Battery Light goes OFF, because it now has 12v(13.5-14.5v) on BOTH terminals so no more ground and no more electricity passing thru the bulb

So do this, unplug the 3 wire connector on alternator
GROUND the green/red wire
Turn on the key
Battery light should come on
If not then a wire is broken

Since you last worked on the cluster you may want to start there with a volt meter or 12v test light
As shown in the diagram, there will be a grey/yellow wire at the cluster that should have 12v with key on, test for that
If it has 12v then ground the meter/test light to the green/red wire(still grounded in engine bay)
Should see 12v(key on)

Ignition switch---------(grey/yellow wire)----------cluster plug>>>Volt meter<<<cluster plug--------(green/red wire)------------------------alternator/ground

If you see 12v then cluster is where the break in the wire is
If you don't see 12v then green/red wire is where the break is, maybe where it passes thru firewall in the BIG round connector

 

Hello,I have been reading some post on this forum all very informative. I think this can help you.

 

Thanks to all who replied to my post.
I was checking a 20 amp fuse in the engine compartment fuse box.
It turned out to be a 15 amp fuse I hadn't bothered to check.