No battery light after removing binnacle.

[Morpheus]

Gents,

I recently removed my binnacle to clean/replace most of the bulbs with LEDs. Of course, I did NOT replace the battery light while in there.

When I connected the harnesses to the binnacle, all the lights seem to work EXCEPT the battery light.

Troubleshooting:
Removed the binnacle, replaced the batt bulb with a new 161 bulb.
Tested continuity between both contacts (+ and GND) on the printed circuit at the harness connection point, checks out ok.

I started to wonder about fuses next, fuse 5 (instrumentation) is ok.

I then tried to do the whole "pull the single wire connector from the Alternator and ground it while turning the key on" trick. Other than burning my hand, no dice.

Then I noticed something that caught me off guard. I noticed that the Alternator wire appears to be attached to a solid brown wire and NOT the brown wire with the yellow stripe. (see pic).
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I seem to remember that the batt light was working prior to all this, but I can't imagine how that is possible considering the brown/yellow wire was tucked up in the harness and taped.

My car IS an early VIN, and i'm sure it has its share of early car weirdness. But, this is a stumper.

[Jonathan]

I've found that the bulb holders can be finicky with being in a good place to make contact properly. Sounds silly, but rotate it a tiny bit forward or back and see if that makes a difference.

[Bitsyncmaster]

Pencil eraser works good to de-tarnish the copper on the flex board.

[Morpheus]

^Agreed on both points, but shouldn't the alternator be connected to the brown wire w/yellow stripe?

[Ron]

Sounds like you need to put a glove on and try the brown/yellow to ground ;-)

[Morpheus]

Ok, I think I found the issue.

I connected the brown/yellow wire to ground and turned the key to 2nd position... battery light.

I clipped the Alternator wire and attached it to the brown/yellow lead. Tested it before connecting to the Alternator, and battery light.

Plugged the pigtail into the Alternator, and no battery light.

Am I safe to assume that my Alternator is shot? I can only assume that being connected to the wrong wire for God knows how long caused some damage. According to the wiring schematic that I have, that brown wire runs to the AUX Relay. Am I correct in assuming that it is not really necessary?

If a new Alternator is in my future, which one is everyone using/recommending nowadays? On my other car I used a Hervey 140A, but the pulley ate belts like they were going out of style.

[Bitsyncmaster]

Ok, I think I found the issue.

I connected the brown/yellow wire to ground and turned the key to 2nd position... battery light.

I clipped the Alternator wire and attached it to the brown/yellow lead. Tested it before connecting to the Alternator, and battery light.

Plugged the pigtail into the Alternator, and no battery light.

Am I safe to assume that my Alternator is shot? I can only assume that being connected to the wrong wire for God knows how long caused some damage. According to the wiring schematic that I have, that brown wire runs to the AUX Relay. Am I correct in assuming that it is not really necessary?

If a new Alternator is in my future, which one is everyone using/recommending nowadays? On my other car I used a Hervey 140A, but the pulley ate belts like they were going out of style.

I'm pretty sure the battery light driver would be toast if connected directly to 12 volts. Your alternator may still work but you will not know when or if it dies.

I'm now using the DMCH high amp alternator and am happy with it since I added the extra sense wire to the battery terminal. I was happy with John's 110 amp unit but had to get another car on the road with it replacing his burnt out 110 amp unit.

[bfloyd]

I'm using a 100 amp "Ultima" alternator for a 1984 Cadillac Eldorado I picked up from O'Reilly 's Auto Parts. Same pulley as the original, and same body mounts too.

[Ron]

Am I safe to assume that my Alternator is shot? I can only assume that being connected to the wrong wire for God knows how long caused some damage. According to the wiring schematic that I have, that brown wire runs to the AUX Relay. Am I correct in assuming that it is not really necessary?It depends on the alternator. Post a pic so we can ID it ..and how it is wired. If you haven't been having charging problems, the odds are that all you need is a regulator. Depending on that and age etc., it is hard to beat a high amp Delco or Saturn w/ lifetime warranty. (Watch for oversize diameter pulleys...OEM are a tad too big already.)

[Morpheus]

It looks like a Houston one to me.
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Is the regulator easy to replace, or am I better off replacing it? The car has run fine with it wired incorrectly for who knows how long.

[Ron]

They are not hard to replace...the thing is, if your light doesn't work, when something (else) goes wrong with it, you will not know and may wind up stranded -- IMO, inconvenience and towing isn't worth the cost of a regulator (or alternator ;-)

[David T]

They are not hard to replace...the thing is, if your light doesn't work, when something (else) goes wrong with it, you will not know and may wind up stranded -- IMO, inconvenience and towing isn't worth the cost of a regulator (or alternator ;-)

The thing to do is remove the alternator and have it bench-tested. If just the voltage regulator is bad most shops will replace it just for the price of the regulator if they can do it without disassembling the whole alternator. Some alternators you can do that and others you can't.

[Jonathan]

They are not hard to replace...the thing is, if your light doesn't work, when something (else) goes wrong with it, you will not know and may wind up stranded -- IMO, inconvenience and towing isn't worth the cost of a regulator (or alternator ;-)

Most notably, that battery light is an early engine overheating warning light as well. If you were to lose your alternator belt, that light is going to tell you about it. What it also is telling you, is to pull over and shut the car off immediately. If the alternator belt shreds, you will also lose your water pump. And with no coolant moving, your engine will overheat and likely damage itself long before the temperature gauge tells you about it.

[David T]

Most notably, that battery light is an early engine overheating warning light as well. If you were to lose your alternator belt, that light is going to tell you about it. What it also is telling you, is to pull over and shut the car off immediately. If the alternator belt shreds, you will also lose your water pump. And with no coolant moving, your engine will overheat and likely damage itself long before the temperature gauge tells you about it.

I would not count on that function. If the alt light comes on it will catch your attention and when you do an instrument scan you will see if it is overheating. Typically the first indication of overheating is loss of power and you have to step further on the gas pedal to move.

[PJ Grady Inc.]

I would not count on that function. If the alt light comes on it will catch your attention and when you do an instrument scan you will see if it is overheating. Typically the first indication of overheating is loss of power and you have to step further on the gas pedal to move.

Actually that is a later indication of overheating when you'er either running on battery voltage which is petering out do to a missing belt or your engine is beginning to seize! I always tell people that if your battery light comes on while you're driving the first thing to do is pull over and check for a missing belt.
That is far more serious then a failing alternator since when the fan belt goes the water pump stops spinning hence the car will overheat quickly. Not everyone knows the battery light can indicate two different things...either your belt is gone or there's an internal fault in the alternater.
Rob