Rdnck84_03
Full Access Member
Correct, if the light illuminates then something is drawing power.
James
James
Batteries 100% drained dead - new problem
- Thread starter RSchanz
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- voltage regulator
Another thing to look out for are relays that should be off when the key is off, but may be stuck in a on position drawing power directly from the batteries even when the key is off. I had the TECA relay on my truck stuck on like that and it took me months to figure it out. Good luck.
BeastMaster
Full Access Member
RSchanz - Frame ( especially something like some metal mounting bracket on the engine ) is considered "ground".
Those big heavy battery cables you just removed are supposed to be connected to the engine block one way or another to carry the heavy return current of the engine starter motor back to the battery negative terminal.
By disconnecting the negative battery terminals - which were the only paths available for battery current to supply the truck, and offering another pathway for that current - now through your test lamp - to get to that same ground, you have forced any current in or out of the battery to go through your test lamp.
Very little current can go through your test lamp, not near enough to power the truck. But it will tell you if something's still trying to draw current. Even as little as a door ajar trying to power the dome light.
This test only tells you if something in the truck is still ON when you think everything is supposed to be OFF. The technique of removing both battery negative cable connectors is standard practice when doing any electrical work on trucks to guarantee you have no electricity, kinda like unplugging an electrical gadget before messing with it's innards.
If you get indication you have a stray current leak, have any friends with a volt-ohmmeter (VOM) that can tell you how much? If you are not familiar with these, get someone to show you. They are easily and irreversibly damaged if not set up properly before measurement attempts.
Many "luxury" things ( power windows, power locks, power mirrors, well just about power-anything but brakes and steering ) often fails when some internal sensor fails to detect some action has been completed and keeps feeding its actuator motor until it senses the job is done.
Brake switches, trunk switches, and courtesy door-ajar dome light switches are common things that don't switch off when they are supposed to.
Suspect EVERYTHING on the "always-on" power bus. If the key turns it off ( and you see other things on that same circuit die ( FSS...the engine and radio die upon key removal ) those are not your problem.
Edit...I just read Tradergems' post...he had a very interesting experience. Yes, what he posted is a likely failure mode of aging mechanical relays. I've already had a glow plug relay fail in a similar manner. It took out an entire set of glow plugs, my batteries AND alternator, with cascade failure of the starter when trying to get my beast to wake up without his morning glow. Just like me if I don't get my coffee. Just grunts and groans.
Those big heavy battery cables you just removed are supposed to be connected to the engine block one way or another to carry the heavy return current of the engine starter motor back to the battery negative terminal.
By disconnecting the negative battery terminals - which were the only paths available for battery current to supply the truck, and offering another pathway for that current - now through your test lamp - to get to that same ground, you have forced any current in or out of the battery to go through your test lamp.
Very little current can go through your test lamp, not near enough to power the truck. But it will tell you if something's still trying to draw current. Even as little as a door ajar trying to power the dome light.
This test only tells you if something in the truck is still ON when you think everything is supposed to be OFF. The technique of removing both battery negative cable connectors is standard practice when doing any electrical work on trucks to guarantee you have no electricity, kinda like unplugging an electrical gadget before messing with it's innards.
If you get indication you have a stray current leak, have any friends with a volt-ohmmeter (VOM) that can tell you how much? If you are not familiar with these, get someone to show you. They are easily and irreversibly damaged if not set up properly before measurement attempts.
Many "luxury" things ( power windows, power locks, power mirrors, well just about power-anything but brakes and steering ) often fails when some internal sensor fails to detect some action has been completed and keeps feeding its actuator motor until it senses the job is done.
Brake switches, trunk switches, and courtesy door-ajar dome light switches are common things that don't switch off when they are supposed to.
Suspect EVERYTHING on the "always-on" power bus. If the key turns it off ( and you see other things on that same circuit die ( FSS...the engine and radio die upon key removal ) those are not your problem.
Edit...I just read Tradergems' post...he had a very interesting experience. Yes, what he posted is a likely failure mode of aging mechanical relays. I've already had a glow plug relay fail in a similar manner. It took out an entire set of glow plugs, my batteries AND alternator, with cascade failure of the starter when trying to get my beast to wake up without his morning glow. Just like me if I don't get my coffee. Just grunts and groans.
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RSchanz
Full Access Member
I attached both positive and did get the test light to turn on. You can see where its been grounded in the images as well (gator clip with red plastic cover).
Now where do I go from here? I have a voltmeter (multimeter) that I can use. Possibly notable things, in the last 6+ months I noticed that sometimes the passenger door doesn't trigger the dome light when open. Also, probably in the last 5 months I added some fog lights. Relay for them can be seen in the image on the right zip tied to the frame. Other than that potential likely causes that aren’t factory and added by P.O. Are trailer brake, and tow lights. Possibly some on shoddy stuff too.
I think regardless of my findings I need new battery cables
Thank you for your detailed descriptions Beast!
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Now where do I go from here? I have a voltmeter (multimeter) that I can use. Possibly notable things, in the last 6+ months I noticed that sometimes the passenger door doesn't trigger the dome light when open. Also, probably in the last 5 months I added some fog lights. Relay for them can be seen in the image on the right zip tied to the frame. Other than that potential likely causes that aren’t factory and added by P.O. Are trailer brake, and tow lights. Possibly some on shoddy stuff too.
I think regardless of my findings I need new battery cables
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Thank you for your detailed descriptions Beast!
asmith
Full Access Member
So in your pictures, everything is off? doors are closed key is out of the ignition? Then you have a draw somewhere. One thing you can do to try and narrow it down is with you test light still hooked up, start pulling fuses one at a time. when your test light goes off you will know what circuit to start looking in.
BeastMaster
Full Access Member
I would have given you the same advice asmith just did.
Tracing these kind of problems is trying, but methodically plodding through will solve it.
You have your test lamp exactly in right area. I could not choose a better place to connect than you did
Judging by it's brightness, it looks like your fault would want to draw several amperes. This is when a clamp on DC ammeter would sure come in handy. I'd love to tell you to measure it with your VOM, but you may be facing high current, which is very risky ( to the VOM) if it's not set up exactly right and you don't have the assortment of test jigs.
Whatever it is, it wants a lot of juice.
Try touching the ground cable back onto the battery post to see if you can throw much of an arc. It's a crude ammeter. A nasty arc means whatever it is means business and reconnection of the large negative cables are ill advised until you isolate the cause. A wimpy arc, something like a tail light might do, most likely is some stuck ON load. Still, reconnection will just drain your battery again.
At this point, you may wire your test lamp in and position it to be easily seen. You are gonna be here a while with other things in your hand. If you feel a bit uneasy with the test lamp constantly on, you may attach a small trickle charger across the battery to keep it up. You will be needing your hands for other things.
The VOM will help you confirm a fault, but you gotta find it first. Key off, all doors closed, everything OFF. The only thing ON is the test lamp.
If you had a heavy arc in the above touch test, it may be a fried alternator diode. Disconnect the alternator to see if that clears it.
No? Maybe it's a stuck glow plug relay. Try disconnecting that big red wire going to one of the two large studs on the glow plug relay.
Still on?
The only thing left tied directly to your battery is the starter motor. Not likely, but I'd give it a try. Disconnect it and see.
If the fault is still there, the only circuits remaining are routed through the fuse box. A really nasty fault should have blown a fuse, but obviously it didn't, So it's gonna be some little gizmo that's not turning off.
One by one, pull fuses to see which one will cause the test light to go out
You may take your time with the troubleshooting. Nothing's going anywhere. Just disconnect the test lamp when it's time for a break. You may be be there quite some time verifying circuit after circuit
Hopefully, get a wiring diagram for your truck. First pull the main fuses, one by one, checking each pull to see if it was the one. Keep tracing back until you arrive at the fault.
Anyone else who has experienced the frustration of this kind of wild goose chase is invited to chime in!
I've done this all too often on both my personal van and on my friend's trucks, and it can get bewildering until one collects an assortment of tools, knowledge, and wiring diagrams.
Tracing these kind of problems is trying, but methodically plodding through will solve it.
You have your test lamp exactly in right area. I could not choose a better place to connect than you did
Judging by it's brightness, it looks like your fault would want to draw several amperes. This is when a clamp on DC ammeter would sure come in handy. I'd love to tell you to measure it with your VOM, but you may be facing high current, which is very risky ( to the VOM) if it's not set up exactly right and you don't have the assortment of test jigs.
Whatever it is, it wants a lot of juice.
Try touching the ground cable back onto the battery post to see if you can throw much of an arc. It's a crude ammeter. A nasty arc means whatever it is means business and reconnection of the large negative cables are ill advised until you isolate the cause. A wimpy arc, something like a tail light might do, most likely is some stuck ON load. Still, reconnection will just drain your battery again.
At this point, you may wire your test lamp in and position it to be easily seen. You are gonna be here a while with other things in your hand. If you feel a bit uneasy with the test lamp constantly on, you may attach a small trickle charger across the battery to keep it up. You will be needing your hands for other things.
The VOM will help you confirm a fault, but you gotta find it first. Key off, all doors closed, everything OFF. The only thing ON is the test lamp.
If you had a heavy arc in the above touch test, it may be a fried alternator diode. Disconnect the alternator to see if that clears it.
No? Maybe it's a stuck glow plug relay. Try disconnecting that big red wire going to one of the two large studs on the glow plug relay.
Still on?
The only thing left tied directly to your battery is the starter motor. Not likely, but I'd give it a try. Disconnect it and see.
If the fault is still there, the only circuits remaining are routed through the fuse box. A really nasty fault should have blown a fuse, but obviously it didn't, So it's gonna be some little gizmo that's not turning off.
One by one, pull fuses to see which one will cause the test light to go out
You may take your time with the troubleshooting. Nothing's going anywhere. Just disconnect the test lamp when it's time for a break. You may be be there quite some time verifying circuit after circuit
Hopefully, get a wiring diagram for your truck. First pull the main fuses, one by one, checking each pull to see if it was the one. Keep tracing back until you arrive at the fault.
Anyone else who has experienced the frustration of this kind of wild goose chase is invited to chime in!
I've done this all too often on both my personal van and on my friend's trucks, and it can get bewildering until one collects an assortment of tools, knowledge, and wiring diagrams.
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nelstomlinson
Full Access Member
The only thing I'd do differently than beastmaster would be to start by pulling all the fuses. If that turns off the test light, then plug them back in one at a time until the test light comes back on.
RSchanz
Full Access Member
Found the culprit I think! Unplugged the wire going from the regulator to the alternator and the light went off. I guess this means my regulator or alternator is bad? See picture below. FYI - the big red wire in the back is currently un-attached but I did the test with it attached.
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Whats odd is every one I've seen had 2 wires going to the alt there. One is for the signal from the regulator, and I think the other goes to your light.
The big rubber dealybopper there that has one wire looped backwards, what does it go to? Looks like someone crimped a splice on it.
The big rubber dealybopper there that has one wire looped backwards, what does it go to? Looks like someone crimped a splice on it.
IDIBRONCO
IDIBRONCO
I had a 1984 Mustang that only had one wire in that plug. Auto Zone told me that it HAD to have two wires or it wouldn't work. Sorry, but it worked just fine.
BeastMaster
Full Access Member
Looks like you nailed it...on the first try!
The following applies to me, if you have the 3G alternator ( voltage regulator mounted on back of the alternator ), this is how I would proceed.
That smaller terminal you disconnected goes to one leg of the three phase alternator stator winding.
Its purpose is to give the voltage regulator a sample of the alternator output voltage - pulsed DC - when the alternator is spinning. No spin -> no pulse. No pulse -> regulator shuts off all rotor drive. Internally, there are three diodes from the alternator field windings ( three-phase ) that feed the big terminal that feeds the battery.
One or more of those three diodes are likely fried. Failed shorted.
Since you are now in safe mode, battery current limited by test lamp, nothing is ON, when you disconnect that sample terminal, the light went off, try grounding the terminal with a piece of jumper wire. The lamp should re-illuminate. This terminal is one of the three phase inputs so a full-wave bridge rectifier. Should do nothing if those diodes are good. All you would do is reverse bias all three positive-feedind diodes. One of those diodes obviously isn't switching OFF like it's supposed to.
I would replace both the alternator and the regulator. There is some sort of catfight going on and I don't have enough info to place blame on who's starting it.
The following happened to me. You may be on my path...
This should clear the woe, but the glow plug relay trying to intermittently fail shorted could instigate this kind of failure. Keep an eye on your voltmeter and be wary of unexplained voltage sags. The glow plugs draw 200 amp from cold battery ~11 volt ( loaded with 200A). Imagine what they will try to draw from a 130 Amp alternator whose regulator is trying to maintain 13.8 to 14 V float voltage!
If your glow plug relay welds shut, you may lose the battery, alternator, all the glow plugs, and possibly a wiring harness.
If you note any unexplained sags, disconnect that one big wire going to one of the heavy studs on the glow plug relay. I wrapped my loose end in shipping wrapping then stuffed the whole shebang in a toilet paper tube to make sure it never touched ground. That wire goes directly to battery rail.
And, for good measure, make certain you have disconnected both battery negatives before messing with the glow plug circuit. You are the one who saves you from the agony and expense of a slipped wrench .
Ask me how I know. I see you on a similar path...
Edit: I just re-read this whole thread.
Your alternator is not the same as mine. That wire you unplugged is probably the rotor brush. You may have just a defective voltage regulator
Replace the voltage regulator first. If you replace the regulator, and the test lamp stays off, odds are you nailed it and the alternator itself may be OK .
The following applies to me, if you have the 3G alternator ( voltage regulator mounted on back of the alternator ), this is how I would proceed.
That smaller terminal you disconnected goes to one leg of the three phase alternator stator winding.
Its purpose is to give the voltage regulator a sample of the alternator output voltage - pulsed DC - when the alternator is spinning. No spin -> no pulse. No pulse -> regulator shuts off all rotor drive. Internally, there are three diodes from the alternator field windings ( three-phase ) that feed the big terminal that feeds the battery.
One or more of those three diodes are likely fried. Failed shorted.
Since you are now in safe mode, battery current limited by test lamp, nothing is ON, when you disconnect that sample terminal, the light went off, try grounding the terminal with a piece of jumper wire. The lamp should re-illuminate. This terminal is one of the three phase inputs so a full-wave bridge rectifier. Should do nothing if those diodes are good. All you would do is reverse bias all three positive-feedind diodes. One of those diodes obviously isn't switching OFF like it's supposed to.
I would replace both the alternator and the regulator. There is some sort of catfight going on and I don't have enough info to place blame on who's starting it.
The following happened to me. You may be on my path...
This should clear the woe, but the glow plug relay trying to intermittently fail shorted could instigate this kind of failure. Keep an eye on your voltmeter and be wary of unexplained voltage sags. The glow plugs draw 200 amp from cold battery ~11 volt ( loaded with 200A). Imagine what they will try to draw from a 130 Amp alternator whose regulator is trying to maintain 13.8 to 14 V float voltage!
If your glow plug relay welds shut, you may lose the battery, alternator, all the glow plugs, and possibly a wiring harness.
If you note any unexplained sags, disconnect that one big wire going to one of the heavy studs on the glow plug relay. I wrapped my loose end in shipping wrapping then stuffed the whole shebang in a toilet paper tube to make sure it never touched ground. That wire goes directly to battery rail.
And, for good measure, make certain you have disconnected both battery negatives before messing with the glow plug circuit. You are the one who saves you from the agony and expense of a slipped wrench .
Ask me how I know. I see you on a similar path...
Edit: I just re-read this whole thread.
Your alternator is not the same as mine. That wire you unplugged is probably the rotor brush. You may have just a defective voltage regulator
Replace the voltage regulator first. If you replace the regulator, and the test lamp stays off, odds are you nailed it and the alternator itself may be OK .
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RSchanz
Full Access Member
That wire runs to the bottom post on what I believe is a battery isolator thats mounted on the passenger side of the radiator. Is that battery isolator an add-on put in by the previous owner not a stock part of the wiring...?
I don't think I have the 3G alternator because my regulator is mounted near the battery on the passenger side. How does that change things? FYI glow plug relay has been bypassed with a manual button in the cab from previous owner.
BeastMaster
Full Access Member
I looked at all the previous posts on this thread and realized that same thing. Your alternator is not the same as mine, so I am in new territory here.
My wiring diagrams are no longer germane, so I am falling back to some old generic experiences
I think that little connector you pulled is the armature brush connector. I am not for sure whether one grounds it or connects it to battery to command the alternator to full output. Maybe someone else here knows.
Whatever, pulling that connection cleared the parasitic drain, so it's obvious that whatever is controlling it doesn't realize the alternator isn't turning, and trying to power the armature anyway
That would be the voltage regulator.
Something is amiss with it's circuit or maybe the regulator is malfunctioning.
I have no wiring info on it so consider I'm shooting in the dark here. Your alternator may still be good. I would inspect the regulator wiring first, if I found nothing amiss, replace the regulator, and if the test light stayed off, reassemble the battery terminals, field test, then do another quickie parasitic drain test just to verify my woe didn't magically reappear.
My wiring diagrams are no longer germane, so I am falling back to some old generic experiences
I think that little connector you pulled is the armature brush connector. I am not for sure whether one grounds it or connects it to battery to command the alternator to full output. Maybe someone else here knows.
Whatever, pulling that connection cleared the parasitic drain, so it's obvious that whatever is controlling it doesn't realize the alternator isn't turning, and trying to power the armature anyway
That would be the voltage regulator.
Something is amiss with it's circuit or maybe the regulator is malfunctioning.
I have no wiring info on it so consider I'm shooting in the dark here. Your alternator may still be good. I would inspect the regulator wiring first, if I found nothing amiss, replace the regulator, and if the test light stayed off, reassemble the battery terminals, field test, then do another quickie parasitic drain test just to verify my woe didn't magically reappear.
Definitely not how it's supposed to be.
It looks like a 1G alt, which is what came stock on these.
Whats odd is it worked before just fine. But I don't think the other device is a battery isolater, because the main discharge line would go to it, not one of the 2 pin connector wires.
It looks like a 1G alt, which is what came stock on these.
Whats odd is it worked before just fine. But I don't think the other device is a battery isolater, because the main discharge line would go to it, not one of the 2 pin connector wires.
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Ole BlackBetty
Full Access Member
I once had a truck that kept killing batteries overnight. took the in had them tested, they said they were fine, charge them up same thing next morning. damanded they replace new battery with another new battery, which they did. next morning dead again. went out after dark to look in truck from outside with doors shut. Noticed dim light in passenger floorboard. the switch to glovebox light had broken and glovebox light was staying on!!
