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having a charging problem on my 1978C3. I have changed the alternator and battery. Cleaned and tightened connectors at starter. Still no out put from alternator. Batter connection reads battery votage and so does the connector on the alternator. Followed wiring diagram and do not see anything else that could be stopping it from charging. Any help would be appreciated.
Not sure if it started red when I fixed a bunch of wires behind the center console and radio area or if it was always like that since I didn't have a radio or ac to put additional drain on the battery.
But it ac radio and all lights and gauges are working now.
I am am wondering if there is something on the printed circuit card behind the gauges or a relay in the system I can't find in the diagram that is not telling the system to turn on.
I have not physically metered out the wires to make to make sure the fusible links are still good. Just assumed since I was getting battery voltage to alternator that they are good
check your warning light. If a warning lamp is connected in series with the excitor wire (between ignition switch and the I Terminal), and a resistor is not used in parallel with the lamp, if the lamp burns out, the alternator will not excite and therefore will not work.
you may have done some wiring work under the dash and bypassed the light or resistor...
Is your charge light working? It should be lit with the key on before starting.
Take a test light (or a jumper wire) and connect between the battery stud and the brown wire (terminal 1) of the connector while the engine is running. If using a jumper just momentarily touch it. If using a light you can leave it connected because the worst that will happen is the light stays lit. either way, see if it starts charging properly after jumpering it.
Is your charge light working? It should be lit with the key on before starting.
Take a test light (or a jumper wire) and connect between the battery stud and the brown wire (terminal 1) of the connector while the engine is running. If using a jumper just momentarily touch it. If using a light you can leave it connected because the worst that will happen is the light stays lit. either way, see if it starts charging properly after jumpering it.
the gen light has never worked along with the other warning lights. That is one of the things I have been trying to fix. I am beginning to think it might be the printed circuit card behind the gauges. All lights tested good when putting to a test circuit I built.
check your warning light. If a warning lamp is connected in series with the excitor wire (between ignition switch and the I Terminal), and a resistor is not used in parallel with the lamp, if the lamp burns out, the alternator will not excite and therefore will not work.
you may have done some wiring work under the dash and bypassed the light or resistor...
the gen light has never worked. Neither has any of the other warning lights. All the lights tested good on a test circuit I built.
I did notice that on a diagram I found on the forum that the gen light appeared to be part of the circuit. But since it goes through the circuit card I assumed it was was for different model.
Well there's your problem. You need the light working to reliably start the alternator. Forget pulling the alternator to get tested at a parts store. Just try the test I suggested and that will tell you it's the light causing the issue.
Well there's your problem. You need the light working to reliably start the alternator. Forget pulling the alternator to get tested at a parts store. Just try the test I suggested and that will tell you it's the light causing the issue.
So, your saying I have probably always had this problem since I bought the car but didn't notice it until I got the AC, radio, fuel pump and other lights working the charging problem appeared evident.
I have been leaning towards buying a new printed circuit card for other light issues (low fuel, seatbelt) but now I guess I have a reason
It could work if you revved the engine or maybe if you drive it enough due to the rotor having some residual magnetism left on it, but basically without the light the alternator won't start charging reliably when the engine starts.
Maybe someone implemented a "fix" in the wiring you cleaned up?
if your sense wire has voltage (lower than it should be as you posted), and you are getting power to the field wire, then there is no reason the alternator is not charging, unless there is a fault in the alternator, or the battery, or the connection betwixt the two. sounds like, without actually being able to test everything, possibly the voltage regulator may be damaged or the rectifier (it happens even on new), or there may be a fault in the charge wire/circuit. test for AC out of the alternator??
According to the schematics, terminal 1 is only powered through the charge bulb. No charge bulb = no power to terminal 1 and no power to terminal 1 = no alternator exciting and no alternator exciting means it doesn't turn-on and start charging.
After I fixed the wires under the dash i must of corrected something the previous he previous owners did. Went back to alternator connector and batter wire was connected to terminal 1 of alternator. Swapped them to were they are supposed to be and presto change o. Alternator now charges the battery.
Will still need the circuit card for the center console dash warning lights to finish that up.
10-03-2016, 10:45 AM
Charging problem
