Charging Light wont go off!

[cetesse]

Hi,

I have Series III 109" with the 2.25L petrol engine -- early 80's exMOD Civilian model.

The charging light stays on ever when the ignition is in the off position and the key is removed. Also the brake lights nor the turn signals work when the vehicle is on.

How do I go about troubleshooting this?

Thank you in advance.

Chris

[brucejohn]

It sounds like the wiring in the ignition switch is quite right. Do the lights work when the ignition is off?

Our hosts have the electrical diagram with color codes and all available on the electrical page. Download, print, grab your multimeter and start chasing down.

Let us know what you find.

[greasyhandsagain]

have the points in the regulator stuck together?


If this is something that just happened right now Id not want to be leaving the battery connected..........

[SafeAirOne]

I had this happen (twice) on my SIII w/ 2.5 NA diesel. Turn off ignition, remove keys, charge light stays on.

My Alternator (or its built-in voltage regulator) went bad. I replaced the alternator with the NAPA equivalent, but the charge light was still on. I took the new alternator to an automotive electric place who tested it and found that the alternator was bad. Got another one from NAPA which has been working fine for the last 4 years.

[brucejohn]

Hey, that all is well and good, but unless my memory is bad the warning light is in the ignition switch circuit. Wired correctly the warning light cannot be on when ignition is off.

[cetesse]

RE: Charging Light wont go off!

Hi all,

Thanks for the replies. The lights do work most of the time when the ignition is off.

If I leave the battery connected it does pull the battery all the way down. The truck sat for 3 years before I got her. So far I've replaced:
1) the battery
2) the starter,
3) starter solenoid
4) and pulled the alternator (and had it tested by the auto shop - it tested good). Its a Delco aftermarket.

She is starting now, and running decent. Still work to do.

How would I test to see if the points in the regulator stuck together?

Thank you,
Chris

[SafeAirOne]

Looking at the wiring diagram (click) the only thing the brake lights (49, 50) and turn signals (18, 19, 20, 21) have in common is that they both get their power from terminal 2 on the ignition switch (23). If the switch wasn't putting out power at terminal 2, the engine wouldn't run (no power to coil (33)).

I think that eliminates almost everything except a bad alternator. You might take it down and have it tested at your local auto parts store.

EDIT: I believe that your alternator (like all series III and modern aftermarket alternators) has a built-in voltage regulatro which, if I'm not mistaken, is solid state and unlike the mechanical regulators on the older series trucks, have no points that open and close regulating voltage. I could be wrong, though--I don't have a 2.25 2/alternator installed in my SIII. Despite your having the alternator tested, I still believe that is the culprit.

[cetesse]

RE Charging light wont go off!

Just a note -- if I disconnect all wires from the alternator - the light stays on.

If I disconnect ground and/or feed from the ignition coil (also just replaced) - the light goes out.

EDIT ... I also modified the stock circuit diagram by adding color to the leads -- might be a bit lazy but found it helpful in troubleshooting. Enjoy the doc.

http://docs.google.com/fileview?id=0B0k4Jw6f3dBpMTBhMmVhNGQtZDFmOC00NDM2LWIyMTQtZjQ2OGFjODEzMGM3&hl=en

(you'll need to download it to view in full color, Google makes it look like a black page)

[SafeAirOne]

Just a note -- if I disconnect all wires from the alternator - the light stays on.

If I disconnect ground and/or feed from the ignition coil (also just replaced) - the light goes out.

What are your temp and fuel gauges indicating while all this is going on?

[cetesse]

The temp gauge moves all the way to top (HOT) when ignition is off. Performs normally when ignition on and engine running.

The fuel gauge is not operable right now.

[brucejohn]

That's right same post as alternator warn light. Ignition switch post 2 is switched on and off with the key, right? If it was wired correctly brake lights and alternator warn light could not be on when ignition is switched off.

Or am I missing something?

[cetesse]

Could it be the ignition switch itself?

[SafeAirOne]

The temp gauge moves all the way to top (HOT) when ignition is off. Performs normally when ignition on and engine running.

The fuel gauge is not operable right now.

Hmm...When the truck is off, the temp gauge should read full cold. Do the turn signals and brake lights work with the ignition in the "OFF" position? I'm wondering if terminal 2 on the ignition switch is always hot with the key in the off position. It should only be hot in the on and start positions.

BTW, are you sure the switch is all the way in the "OFF" position when you removed the key? My "key" can be any thin, pointy object and can easily be romoved with the switch in any position. In fact on washboard roads, my keys fall out all the time.

EDIT: I've also had to change my ignition switch as it refused to energize terminal 2 in the "run" position.

[SafeAirOne]

It sounds like the wiring in the ignition switch is quite right. Do the lights work when the ignition is off?

Ahh... I think brucejohn and I are arriving at the same conclusion, except he is way ahead of me. I'm going to presume the above quote is a typo and that you meant to say "It sounds like the wiring in the ignition switch is NOT quite right."

In that case, I'm beginning to agree.

[cetesse]

Pretty sure the key is all the way off. Straight up & down and the cylinder pops out flush with the casing.

The turn signals aren't currently working but I think that's the flasher unit - trying to get the charging light fixed first. The emergency brake light only comes on (briefly) when the ignition first starts up. The brake lights aren't working, but like the turn signals they did briefly work when the truck arrived a month ago.

How hard was it to change out the ignition switch? I imagine just not a lot of room to work?