Alternator charge light problem

ox_ford_guy · #1 (**permalink**) 10-15-2006, 01:17 PM

Help any electrical experts out there......

As with normal operation, the alternator charge light on my Backdraft Cobra dashboard goes on when I turn on the key but do not start the engine.
However, once I start the engine it stays on and does not go off until I turn the engine off.

The alternator appears to be providing just under 14.5 volts when running and the motor will continue to run when I turn off the battery switch. I think this indicates that the car is getting the proper charge and I have not had any dead battery issues yet. I just can't get that light to go off and it is quite annoying..
(The previous owner had the light dissconnected from the lens holder and hung under the dash probably because of this issue.)

All that the Backdraft manual says is to connect the small yellow wire from harness to the alternator for this light to monitor proper charging function.
(Not a very specific instruction)

As set up now, the yellow wire from the harness is connected to the "i" terminal on the "asi" connector block on the alternator. The large gauge red wire goes to the alternator feed lug and a smaller gauge red jumper wire goes from the alternator feed lug to the "a"terminal on the "asi" connector block on the alternator. The "s" terminal on the "asi" block has nothing connected to it

If I disconnect the yellow wire from the alternator "asi" connector block the charging light goes out but the alternator won't put out a charge as the engine runs and the Volt meter reads about 12 volts
(If I turn off the battery disconnect the car dies indicating that it was running on battery power only)

I have tried connecting the yellow wire to the other "asi" terminals but the charge light doesn't work at all when I do this...

Is somthing hooked up wrong, or is the alternatior bad, or ???????
Also, what do the "asi" markings mean?

No markings on it, but I believe the alternator is a Ford unit with internal regulator setup.

Any help would be greatly appreciated...Thanks..ox_ford_guy

Ron61 · #2 (**permalink**) 10-16-2006, 05:54 AM

I am not sure this will be of any help at all as I have no light, just a dash mounted volt meter which reads my battery and shows what voltage the alternator is putting to it. Do you have a volt meter, and if so, does it work correctly, IE shows 13/15 volts when running and nothing once the engine is shut off? If everything else is working ok, it would almost sound as if you just have the light wired wrong. It is showing charge when the engine is running and should only light when you lose the charging, such as when you shut the engine off. I am not familiar with your wiring set up, so will have to leave that to the people who are. Sorry I can't be of more help.

Ron

sharpe 1 · #3 (**permalink**) 10-16-2006, 06:14 AM

What is the brand of your alt. ?

trularin · #4 (**permalink**) 10-16-2006, 07:34 AM

If it is any help, there is a schematic of a 65 T'Bird on my gallery. I think it has a change lamp.

ox_ford_guy · #5 (**permalink**) 10-16-2006, 09:57 AM

Ron 61...Thanks for the reply. The car does have a voltmeter that shows just under 14.5 volts when the car is running and shows nothing when the car is off with key off. With key in on position but motor not running the voltmeter reads 12 volts.

Double checked with my multi-meter to verify gauge readings.

Battery is charging but the light stays on...It's a mystery..ox_ford_guy

ox_ford_guy · #6 (**permalink**) 10-16-2006, 10:04 AM

Sharpe 1....Thanks for your reply
I took off the alternator for a complete look but cannot find any Manufacturer stamp or tag on the unit.

The number 22-208 and Made in USA is cast into the aluminum casing and this all I can find. Is there any way I can trace the manufacturer.?

Thanks..ox_ford_guy

ox_ford_guy · #7 (**permalink**) 10-16-2006, 10:20 AM

Trularin...Thanks for your reply....I am going to your gallary for a look at the
schematic to see if it helps..Thank.....ox_ford_guy

Ron61 · #8 (**permalink**) 10-16-2006, 10:23 AM

Ox_Ford_Guy,

Your volt meter is showing correctly and everything is working ok then. As for the light, I looked at the wiring schematic of my 69 Torino cobra and the light comes off a different lead and will only come on if the voltage drops to about 6 volts I believe it is, but I use the gage anyway. It sounds as if your light is wired in series with the output the same way an amp gage would be and it shouldn't be. I don't really like the light and I just disconnected mine and go by the volt meter. If you can't find an easy solution, you could just wire around the light as it is redundant anyway since you have a voltmeter that shows your battery voltage. I tried to see the numbers on my alternator as it is the original one and has an aluminum case, but I can't see anything in there without getting under the darn car with a mirror.

Ron

ox_ford_guy · #9 (**permalink**) 10-16-2006, 10:52 AM

Ron61

Ron...Thanks for your extra efforts on my behalf. I may end up with a wire around, if all else fails, as I have spent alot of time on this one with no positive outcome. I do have a voltmeter so the light is redundant and everythings seems to charge properly. (I get a little hung up on these technical glitch things sometimes)

If I do a wire around, do you know if I should in-line fuse the circuit and at what amperage should the fuse be? Thanks again...

ox_ford_guy
Gordon Clarke

Rick Parker · #10 (**permalink**) 10-16-2006, 11:00 AM

Are you using a separate voltage regulator? If so, the light is controlled by the action within the remote mounted regulator. One side of the bulb gets power from a switched 12 volt source (or direct from key switch) and the other side is grounded by the regulator after passing through the fuse panel or being connected directly to the regulator. When enough current is created by the excited alternator, the circuit grounding the bulb is switched eliminating the ground and causing the illuminated bulb to go out. On the old voltage regulators, this was done with a set of mechanical points and electromagnetic energy, on the new regulators, transistors do the switching.

ox_ford_guy · #11 (**permalink**) 10-16-2006, 11:09 AM

Rick Parker...Thanks for your reply. No, the alternator is an internally regulated unit, as far as I can tell.
There is no other regulator on the car that I can see...
Thanks..Ox_ford_guy

Ron61 · #12 (**permalink**) 10-16-2006, 11:26 AM

If you do a wire around I would fuse it just in case, but I really don't know what size fuse would be best. Rick can tell you more about that than I can.

Ron

ox_ford_guy · #13 (**permalink**) 10-16-2006, 01:16 PM

Rick...Maybe then it is a transistor inside the internally regulated alternator?..If I decide to do a wire around (last resort) what amperage in-line fuse would be appropriate? Thanks for responding...ox_ford_guy

trularin · #14 (**permalink**) 10-16-2006, 01:44 PM

Are you sure you have a 12V bulb for the ALT light?

Just asking.

ox_ford_guy · #15 (**permalink**) 10-16-2006, 02:05 PM

Trularin...Bulb has 12V 2A stamped on the base..Does this sound right?

ox_ford_guy

Rick Parker · #16 (**permalink**) 10-16-2006, 05:36 PM

Please deleate this post

Rick Parker · #17 (**permalink**) 10-16-2006, 06:31 PM

More likely 12v 2 "W" (watt).
Pretty common bulb for our gauges.

ox_ford_guy · #18 (**permalink**) 10-16-2006, 07:08 PM

Rick..Your right...Don't see to well anymore..Thanks..ox_ford_guy