Ignition warning light on all times?

Grubby · #1 (**permalink**) 02-22-2011, 03:00 PM

Should me ignition warning light be on all the time when the key is on? I got the car late last Summer and just noticed the red light is on all times if the key is on.

I assumed from reading the manual and wiring diagram that the light indicates a charging problem.

Please explain.

John

patrickt · #2 (**permalink**) 02-22-2011, 04:01 PM

Quote:

Originally Posted by Grubby

Should me ignition warning light be on all the time when the key is on? I got the car late last Summer and just noticed the red light is on all times if the key is on.

I assumed from reading the manual and wiring diagram that the light indicates a charging problem.

Please explain.

John

Yes, if the engine is not running and the key is in the "On" position. No, if the engine is running.

Excaliber · #3 (**permalink**) 02-22-2011, 04:35 PM

Usually it's the other way around, no light and as a result, no charging either!

That light is in the voltage path to the regulator that in essence, "turns on the voltage regulator" which in turn excites the alternator and lets it start charging. No light, no excitement, no charge.

,,,strange that it is staying on, I wonder if that is indicative of the voltage regulator being bad, in that the voltage remains high in that circuit? I hope someone weighs in on this problem with what to look for.

Meanwhile, I'd double check all the voltage regulator wiring connections to make sure each one is making a good contact. Look inside the plastic plugin connector and see if any of the wires are pushed back in to far and not making contact where it plugs in.

I am of course assuming your alternator is charging normally, as you seemed to indicate that is the case. I'd also run a voltage test at the battery to make sure it's not over charging because of the possibility of the voltage regulator being bad. Voltage should not exceed 14.5 volts at a fast idle rpm if the regulator is working properly.

strictlypersonl · #4 (**permalink**) 02-22-2011, 04:38 PM

Pat's correct. The light should go off initially when the engine is revved above about 1200 rpm, after that, above about 600 rpm.

What does the ammeter show at 1500 rpm with the fan on? (You can turn it on with the override switch.)

Excaliber · #5 (**permalink**) 02-22-2011, 04:54 PM

I see Bob is NOT assuming the alternator is charging. Good call Bob, back to basics and establish fundamentals first!

Bad ground at the regulator maybe? That light connects to the "I" terminal of the volt regulator, by the way.

Grubby · #6 (**permalink**) 02-23-2011, 06:25 PM

My ammeter shows about +25 with the bright headlights on and heater. I managed to break the cooling fan switch while installing the carpet and have not got the replacement yet. System voltage running is just over 14. I say it is charging.

Any other thoughts?

Thanks.
John

Wbulk · #7 (**permalink**) 02-23-2011, 06:45 PM

See if the wire between the light and the I terminal is grounded somewhere. Disconnect the wire at the I terminal and the light should go out. If not it is grounded between the regulator and the light. Other than that the regulator may be defective and the circuit is grounded when running when it should be open.

Excaliber · #8 (**permalink**) 02-23-2011, 07:07 PM

Well, I'm scratching my head! I keep looking at the wiring diagram and drawing a blank on what might cause this.

The only thing I can come up with....
One side of the warning light gets 12 volts directly from the ignition switch. The 12 volts passes through the "light bulb" and then continues on to the voltage regulator "I" terminal. IF that "I" terminal wiring back to/from the red light is grounded along it's path (between the light bulb and the "I" terminal) the warning light will stay on. I don't have a schematic of the internal wiring of the V.R. itself,,,, bummer. I SUSPECT the voltage regulator cuts off the ground internally when a charge rate is detected. If so, thats why I suspect the V.R. is bad.

ERA 778 · #9 (**permalink**) 02-23-2011, 07:08 PM

Your problem reminded me of something i read some time ago and it took a few minutes to track it down. Your situation sounds somewhat like the problem described in MSD's Troubleshooting Guide for their 6530 ignition boxes:

"ENGINE RUN-ON
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing Run-On, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off.
Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. Figure 14 shows the proper installation for early Ford and GM vehicles.
Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed
facing the proper direction (as shown in Figure 14).
Ford: Install the Diode in-line to the wire going to the #1 terminal.
GM: Install the Diode in-line to the wire going to terminal #4.
Figure 14 Installing the Diode to fix Run-On."

You might have just part of the symptoms.

You can download the entire manual from MSD's website.

Hal

Grubby · #10 (**permalink**) 02-23-2011, 07:11 PM

Hal,

I actually have engine run on to. The diode is worth while just to fix that and I may get lucky and fix two problems at once.

John

Grubby · #11 (**permalink**) 02-23-2011, 07:22 PM

I just went through the extra parts that came with the car. The diode is in the MSD box. I bet one problem will be fixed and if I get lucky - both.

John

Wbulk · #12 (**permalink**) 02-23-2011, 07:44 PM

Hal may be right. I do have the diode in my car. However I don't believe the 60s cars had them. The diode keeps the alternator current from flowing back through the light and making it's way to the ignition coil.

Make sure you put the diode in the right direction. It should be between the light and the regulator.

Wbulk · #13 (**permalink**) 02-23-2011, 09:04 PM

Ok, I have been thinking about this. I don't think that is the problem. When you shut off the engine there is residual current that can flow back through the I terminal, but not when the engine is running. The diode is to stop that residual current that only last for a second or so. I looked at some old 60s regulator diagrams and they didn't add those diodes until later. You should still put that diode in. But it's purpose was just to stop run on after the ignition switch is turned off.

Wayne

strictlypersonl · #14 (**permalink**) 02-24-2011, 08:37 AM

Much of what can be said, already has, but...

I would first check the ground at the voltage regulator and the firewall ground connection near the starter solenoid. If they are both good...

Remove the plug from the voltage regulator and (with the ignition on) check the voltage at the plug's green/red wire. It should read 12V.
Ground that terminal. The warning light should glow brightly.

If those things check out...

Replace the voltage regulator.

Grubby · #15 (**permalink**) 02-25-2011, 06:37 PM

The dash light goes out when the I wire is backed out of the VR plug. Grounds checked good with Fluke and they are tight and clean. The Green/Red wires shows system voltage and when grounded the dash light comes on.

All points to a bad VR. I will pick one up and report back.

I did go ahead and solder the diode in the see it it improves the run on problem.

John

Grubby · #16 (**permalink**) 03-01-2011, 06:13 PM

Installed VR. Dash charge light on at all times and the alternator did not charge. I just replaced the alternator tonight with another Delco rebuild. All problems are fixed.

It seems the VR had a short or something that would not turn on the dash light, even on key on / engine off. I noted DC output from the stator on the alternator was only about 6v. The replacement alternator is much higher. This must be related to the old alternator not working with the new voltage regulator.

New VR and alternator required for fix. The old alternator did test bad at AutoZone, even though it seemed to be charging on the car. Seems a bit strange, but the problem is fixed for under $100.

John

strictlypersonl · #17 (**permalink**) 03-02-2011, 06:17 AM

Grubby,

That's interesting. I'll have to put your experience in my mental database.

The only explanation that I can think of is that one (bad) diode bridge in the alternator was triggering the light.

Grubby · #18 (**permalink**) 03-14-2011, 03:22 PM

The replacement alternator lasted less than 100 miles. I tried to full field it and got nothing. The local Delco supplier stepped up and replaced the alternator. Problem fixed again.

Maybe this one will last.

John

ZOERA-SC7XX · #19 (**permalink**) 03-14-2011, 06:45 PM

Quote:

Originally Posted by strictlypersonl

Grubby,

That's interesting. I'll have to put your experience in my mental database.

The only explanation that I can think of is that one (bad) diode bridge in the alternator was triggering the light.

The problem in my ERA (light on while running and not charging) was a bad fuse (fused link). Replaced it and it was fine. Check the simple stuff first.

WarrenG · #20 (**permalink**) 03-14-2011, 07:09 PM

I have the opposite situation. The red charge light never comes on. Not sure when it started, never took notice of it until somebodyelse pointed out that it didn't come on when I turned the key to the on position. I replaced the ignition switch recently is it possible that I reversed a couple of wires? Never had one of these bulbs burn out before but I suppose I should check that sometime.