Hi All,

This is actually in my 1996 Explorer, but I know many of the same tech applies to the 96 Aeros as well (same engine, etc)

I changed tstat last night and new engine temp sensor too, all is well with cooling system, etc... no more codes...

but when I put everything back together, and started the truck, I get a red battery light on the dash that wasn't there right before I did the tstat

When I pulled the gooseneck off the front of the block, of course, water gushed out, etc... I've done this before though, and never had anything happen like this.

The alt and battery both check out good, both at idle and under load... the light is constant, no matter what the RPM, etc...

So, I'm thinking now that maybe the sending wire or sensor for that indicator is bad, knocked off, etc... and I'm trying to figure out where that wire comes from, so I can address the issue, since it's kind of annoying, and I would like the like to one come on, if there really is a problem with the car's electrical system.

I get 13 volts at the battery, engine off - 14.5 at the battery at engine idle... load test passed too, as the alt generated more amps at 2K than at idle, even with a load (high beams, heater fan on high, etc)

the gauge is right in the middle as well, so if it was under or over, I would think it would show me that too?

any help would be great... thanks!

 

blown voltage regulator/charger indicator module in alternator from ethlene glycol bath.
easy to change, about $15
check brushes at same time
clean slip rings with acetone
all will be gummed up from the douche

 

would water have done the same thing?

so, pull the alt, and then what? do I have to tear it all down? or just replace something, like a module? Where are the slip rings? inside I guess?

will it ruin anything if I drive it as it is?

thanks Cliff :-) I knew you'd know the answer...

 

No you should not have to pull the alternator to change the voltage Reg. This is the little regulator box attached to the alternator which you unbolt & slide out , also has the carbon brushes attached with the electrical 3 pin plug attached to it. Given the values shown your alternator is working O.K. though. however you may not be getting full load current from it, this test is more difficult without a proper tester. The red light can normally only come on if the field wire is near 0v or the bulb wire is shorted to ground (on the alternator side).

 

The way it works is one side of the bulb is tied to 12v and the other side goes to the alt regulator..when the alt is not spinning the wire is close to ground potential so the light comes on. When alt is turning the light wire is supposed to come off ground and go up to 12v or so shutting off the light. 12 volts on both sides of the light will cancel out..

The alt is easy to get out so take it off..Take two or three torx screws off the regulator brush assembly and twist out.. Get new reg and possibly brushes as said above.

Also if the wire came off the light would be off. And if the wire came off the alt wouldn't work as it needs that light circut to work..
Dick

 

Thanks all - sounds like what Cliff said - but I was also advised to check the generator fuse? could this be blown and still allow the alt to charge?

where can I buy just the regulator? are the brushes hard to re-install? or does this whole unit just kind of slide in place, and then you tighen back down the torx head screws?

It does look easy enough to pull - just those 3 long bolts, right?

Maybe before I pull it, I'll try some contact cleaner on the little wire's contact, and make sure it's well connected there... that's the one in question right? not the plug with the 3 connection on it... correct?

Thanks all

 

alternator exploded view 3G Ford
Ford Motorcraft Type 3G Series Alternator Exploded View

National Quick Start Sales, High output alternator, Alternator & Starter Parts - Voltage Regulator

 

ok,

so I went to my local parts place, and got a new VR, and the brushes, since you have to take them off anyways, figured I might as well just get those too...

cleaned the slip rings, re-assembled, LIGHT IS STILL ON!

Re-Checked volts at batt - 14+ just as before KOER... I even cleaned up the battery terminals, etc too, just for PM, since I had them off anyways...

so it wasn't the VR... any other way I can figure out how to turn that light off? - I know the charging system is fine in the truck, and also had it checked on one of those machines too.

I did check AC at the battery too, and there was nothing, so there is not a bad diode on the rectifier, etc...

Im going nuts here with this stupid thing! :-)

Actually- I just had a flash....

The little 2 conductor wire does NOT connect to the VR anyways I noticed, as I recall, only the larger 3 wire plug does, correct? so it could still be something in the Alt not giving me 12 volts to that wire back to the switch? whereever that smaller 2 connector wire goes inside of the alt?

any other ideas?

Thanks

 

BTW - one other question - does anyone know for a 1995 or 96 if ford would had used both the 95 and or 135 amp alts? - or did they only use the higher one on the V8's?

I just was curious if anyone knew what was the OEM for the 4.0L OHV

 

90 amp I think...Other ways for the light to stay on.. The wire for the light has to be grounded somewhere or you have a dash problem.

My wire is a LG/R light green and red...Might be shorted to ground somewhere...pinched
maybe.

Dick

 

so, this is the smaller, single conductor wire that plugs into the alt housing? it's not part of the larger plug that connects to the Voltage Regulator, right?

I guess if I'm daring enough, I can see if I have 12 v right at the clip connector, while the engine is running - might be a good way to loose a hand :-)

Actually - I could see if the wire itself has 12v somewhere down

this all happend after some liquid was introduced around this area to wash down the the antifreeze in and around the gooseneck, etc when I changed the tstat...

but the only wire in question here is the little guy, that is alone, correct?

 

check color..

 

Unplug the 3 wire connector to reg.. key on and light should be off if not the wiring back to the dash is suspect..

 

Yes, when I pull that plug, the light is off with KOEO - so, does that mean the wire is the problem?

 

That means the regulator is bad..Usually. you may have gotten a bad one..