Thanks Hellokit. Since the OP stated that he has removed one red wire and everything seems to work except the alternator I am assuming that wire is for the regulator lead of the alternator. The drawing you provided a link to shows the field lead going to the dash light, as it should. I’m pretty sure if he ohms out the lead it will confirm that.
Jqutie,
I think I understand what you have been saying, most of the time at least. Some of your statements on what you did are kind of vague though. Have you tried measuring the resistance of the disconnected red wire and the small red wire to the alternator yet? It would help us to know if that wire ties to the alternator. I am pretty confident you will find it does tie there.
Sorry, no, with all the unrelated severe weather, power outages, computer ISP outages, home owners insurance problems, pet problems, etc. I put in a different recharged battery and still had (WITH negative battery ground cable and single wire [to alternator field?] DISconnected) +9.8 on alternator-to-negative terminal post (previously 9.5v). That’s all the new data I have, but it implies strongly [to ME, but what do I KNOW?] that I have TWO shorts to ground - the single red wire from the +post at the solenoid which can instantly drain a battery by confusing the swithches in the solenoid/starter, and a short in one or the other red wires on the single connector to the +post on the solenoid (which are necessary to get the engine to run, but which never drain a battery instantly.)
Well ok I understand.
I see you are still taking voltage measurements with the negative battery cable disconnected. I have tried to explain to before why you are chasing your tail by doing that. Those are not shorts you are seeing there. They are just some sort of load and most likely not a problem. If you want to prove this to yourself try doing your test the same way on another car that has no problems and see what happens. You will see it gives you the same results you are now seeing except the voltage may be different due to the load difference. What you really are trying to do is a current test using a voltmeter. A current test is done with the ampmeter in series with the circuit and voltage is always measured across some device. Like across the battery terminals or to the power lead of a light and chassis ground.
Edit:
Another question. In your original post to this problem you stated that the battery voltage went down to 4 volts instantly. I would like to know where that reading came from. I suspect it came from the meter in the dash. Is that correct? If that is so then I think we have a connection problem in the power bus between the positive battery post and the accessories. This is the only other thing that I can think of that would make you think the battery going that low in voltage and a volt test at the battery terminals would show a different voltage.
COUGAR: You may be right, but I can’t verify as the VW is away at college. I understand that there are “hot at all times” terminals in my car. They may or may not be used at ALL times by radio/CD player [aftermarket], perhaps the engine controller, etc. BUT, even so, WHY would they be sending 9.5 or 9.8 +volts to ground ALL THE TIME??? This would drain slowly a battery overnight, wouldn’t it??? I get this with ALL fuses & circuit breakers pulled from the fuse panel and everything turned off. To ME, this means a short-to-ground [or two shorts]. TRUE, it voltage disappears when I reconnect the negative battery cable. But GIVEN all this, HOW could a battery be INSTANTLY drained below 4v with the key igniton to START with all three small wires or only the one single small wire connected to the +post on the solenoid??? We keep conflicting over this same difference with no resolution. Granted, I need to do a coupla suggested tests for additional info. Please be patient with me - several turds hit the fan in the last several days.
Please reread my previous post as I have added to it.
You are correct about the current load on the battery and there is a normal current drain in todays cars to keep things like memories alive. The current drain is real small, on the order of milliamps so the drain on the battery is real small. The voltage you are reading could very well be from those type of things. It isn’t 9 volts they are sending out, they are connected to 12 volts (at least when the ground wire is connected to the battery and chassis correctly) and you are measuring a voltage (in the wrong place) due to the current the loads are using. The current draw they are using isn’t going to kill a battery instantly. The voltage doesn’t disappear when you connect the ground back, it gets distributed properly back across the load in the circuit. You are trying to make your high impedance voltmeter part of that circuit by adding it in series with the load. It is a meaningless test procedure.
As far as the the 4 volt reading I think my previous post may explain what happened. When you understand series circuits and voltage drops you will see what I am talking about.
Hellokit, Oldschool, Tardis, along with myself and a number of others here have a very good handle on electrical troubleshooting. If you follow the advice we give you, you will find the trouble.
Cougar: Re your edit - WRONG! The less than 4v across the battery terminals, BOTH disconnected and the battery removed, AFTER the INSTANTANEOUS drain with all connections to the +post on solenoid, measured by an external voltmeter [which reads 12.6 volts across the same battery recharged 12 amp/2amp-recharged battery.The rapid recharge @ 12 amps verifies that the battery was REALLY badly discharged!]
I can’t disagree with your original paragraph, but I don’t have a 2nd car with which to verify using the same equipment.
My sense is that you and I have a “disconnect” - I’m reporting repeatedly valid info and you are denying the feasibility based upon some unconscious assumption, misunderstanding of my accurately reported results, or some lack of understanding of the INTERNAL electricals of the solenoid/starter combination re instantaneous battery drain possibilities. Your CONTINUOUS helpful attituse [along with that of others] is MOST appreciated!!! But you keep coming back to the point that there is NO way that a battery can be drained to less than 4v INSTANTANEOUSLY by turning the key ignition to “Start”. Believe me, I’ve now done it numerous times, to the point of having protected A/C outlet trip when plugging in the battery recharger after connecting it to a removed, drained battery -several times! BUT, the battery drain ONLY occurs when I have the small, single red wire connector on the +post of the solenoid. This should be a big CA-LUE! But no “experts” seem to be able to solve the problem. They all say, “It’s the alternator!” or “It’s the starter!” or “It’s the solenoid!” or “It’s the battery!” With the starter, solenoid and alternator REMOVED, I can connect the +cable from the battery with both connectors of three small, red wires and INSTANTLY kill a fully-recharged battery to less than 4v when I turn the key to “Start” [nothing having happened when the key went to “Run”, as verified when battery is disconnected and tested, and when placd on the battery recharger.
Ok, you have made your point and I will go by what you have seen and experienced. Please forgive my doubt in what you have been trying to say all along. I can be pretty stubborn when I think I have things figured out and then don’t listen very well. Your last few statements tell it like it is. This problem will be one for the books alright.
You know which wire is causing the trouble. Didn’t you state somewhere back that you can leave that wire disconnected and everything worked except the alternator wasn’t charging?
Lets see what the resistance to ground of the troubled red wire is in the START mode. Remove the positive battery lead from the battery. With everything else connected normally except the red wire and the positive battery connection isolated from the battery and anything else, place the ohmmeter leads on the red wire and a good frame ground point and see what the resistance is. Then turn the key to the START mode and see what the resistance is. Does it connect to ground; go to zero ohms?
Just to be clear, when you say the, “starter and alternator removed”, do you mean that EVERY wire (and battery cable) is removed from each component, and that all the disconnected wire terminals are isolated and insulated from contact with each other and from anything else?
You, then, can touch the disconnected three small red wires (two of the wires on one terminal) to the battery positive terminal, and the battery instantly discharges to about 4 volts? Is that correct?
With ALL the wires disconnected from the alternator and solenoid, isn’t a positive battery cable connected to the power distribution center? And, what is the single little red wire shorted to? Could it be energizing something which connects the positive battery power to ground? Perhaps, inside the power distribution center?
As Cougar said, you need to follow the yellow brick road, er, I mean, the little red wire (electrically).
COUGAR: We all have that problem sometimes when we jump to a wrong conclusion. I’m now convinced that I stubbornly stuck with the 9.5v measurement wrongly.
With that one wire off the +post of the solenoid and isolated, the solenoid/starter works fine, cranks the engine rapidly, and the engine runs. Dash voltmeter shows about 11v steady and battery slowly loses voltage to below 12v with many starts.
Have a list of suggested test measurements to do from all the posts above and will add yours and try to get some today if it doesn’t go to the shop for radiator replacement.
Hellokit,
Isn’t this problem something else? It will be interesting to find out what the resistance to ground is of that red wire when in the START mode and what it ties to. To me, it seems it has to be tied to the ignition switch.
Jqutie,
As far as your list of tests goes if you have any previous requests from me just forget them. I now just want to know what the resistance to ground is of that red wire in the RUN mode and the START mode. It’s a different ball game for me now.
EDIT: I think Hellokit and any others would agree with me that tracking down this wire is the priority now and any other things are secondary.
“With that one wire off the + post of the solenoid and isolated …” This quote illustrates part of the problem in communication I (we) have. YOU know which (of several wires) you are talking about, and which + post (of two, or more posts) YOU are talking about; but, the collective ME doesn’t know.
Now, if you would name the which and the which, throughout your narratives, it would clarify things, muchly.
ALL: Voltages to S post were 0v key off, 0v key=Acc, 0v key = Run, 8v key in Start, engine started quickly, released key back to Run and again it was 0v. All as expected, right?
With that single red wire disconnected from +post of solenoid, engine running, wire disconnected from +post of battery, alternator output was 2.7v higher than ground at alternator bracket. Ground must be 9.5v? Total = 12.2v???
To prove HK wrong, jumpered +battery to isolated red wire. Battery did NOT die when ignition key turned to Start, but started engine and dash voltmeter was reading 14v! In disbelief, removed the jumped and put the isolated red wire on the +post of solenoid, so ALL wires were connected normally. Engine cranked and ran and dash read 14v from alternator. The cause has DISAPPEARED - at least momentarily, after two dozen or more failures in a row with normal connections. It may still be intermittent, so stay tuned! I really don’t want to mess with the wiring until after I get the rad and fan clutch replaced so engine doesn’t overheat.
Jqutie,
I think the red wire that has been causing the trouble may go to the alternator. You know the alternator wasn’t working with that wire removed and now it does work when the wire is tied to power. To verify this remove the positive battery lead from the battery. Turn the key to the RUN position, then place the ohmmeter leads between the mysterious red wire only and the small red wire, disconnected, from the alternator. See if you have continuity there. I suspect you will. You don’t need or want to start the engine to do this test.
As a note. A good working alternator should run between 13.25 and 14.8 volts DC. Also, unless the grounding system has a connection problem it always should be 0 volts when used as a voltage reference. This is where you are getting confused. Ground is ground and if any voltage can be measured between the negative battery post (the true ground reference point) and any other supposed ground point then that point isn’t bonded to true ground reference, say like the chassis should be. If the negative battery clamp gets corrosion between the negative battery post and the clamp connection to the battery then a voltage drop will occur between the battery post and the clamp when current flows through whatever that resistance is. Then the whole car chassis will be at some voltage above what the true ground should be.
COUGAR: I agree that the troublesome red wire must be the +feed to the alternator’s internal controls. Do you mean that BOTH small, red-wire connectors should be disconnected from the +post on the solenoid and the ohms read between them?
Sounds like my alternator is generating at full power! Remember that the -connector to the battery was removed when I did those v-checks and got 9.5v.
I am just trying to isolate both ends of what I think is one wire. So just the one red wire end that you were having a problem with when it was connected normally, and the small red wire going to the back of the alternator. See what the resistance is between those two ends. To be safe, first remove the positive battery cable on the battery before you do the test. Check the resistance of the wire while the ignition switch is in the RUN mode and in the START mode. If you have close to zero ohms with the switch in the RUN mode that should be normal. In the Start mode I think that wire connection should be open but I can’t say that for sure.
I agree that the alternator is working now and we may now never know what really happened unless the problem reappears. I don’t know if you disconnected the battery ground cable while the engine was running but in case you aren’t aware of it the battery should never be disconnected while the alternator is running.
Boy! We’ve beat this por’ ol’ hoss, hain’t we? One last whuppin’ an’ maybe we kin let’er go.
I pointed out that there is a fusible link section in each of the small-red-wires. A fusible link is a smaller gauge wire section (with a thicker covering) which, because of its smaller size, will melt and break the circuit through the wire if too much amperage goes through the wire. Sometime, the fusible section will melt; but, the wire might move, just a little, and the wire kinda welds back together, or the wire ends may be close enough together that current can jump the gap and flow again.
Any whoo, you need to check the fusible link by disconnecting the connector at the alternator that has the little red wire. Attach positive voltmeter test lead to the little red wire at the alternator (attach the black test probe lead to ground). The little red wire should have the same voltage as the battery. While maintaining that test connection, SHAKE the little red wire (shake the wire bundle) throughout its length. The voltage should remain at battery value. If it doesn’t, it may be because of the melted fusible link. Replacement fusible links are available at the Chevy dealer. [Man! These things take a heck of a lot longer to type up than to do!]
COUGAR: Two connectors, one with a single wire (the suspected one), the other connector with two equal wires went to the +post on the solenoid, along with the big +cable from the battery. You want me to disconnect the +battery cable and both solenoid connectors and check the continuity between the two connectors at their solenoid ends?
I never disconnect battery cables while the engine is running.
HELLOKIT: Yea, this is a well-beaten horse with 77 posts! There are NO visible fusible links on any of the three small, red wires at the solenoid end. There is only about 4" of exposed wire before they dive into a conduit to somewhere. They must be on the other end, wherever that may be?
The +post at the solenoid is the source of battery voltage to all three small, red wires. If I disconnect them from the solenoid, how can they show any voltage???
I didn’t say to disconnect anywhere except at the alternator. And, it doesn’t matter if the ignition key is ON, or OFF.
I’m asking you to take a voltage reading at the alternator; whereas, that other feller is asking for an ohm reading. There are similar reasons behind both requests.
The section with the fusible link will be thicker than the rest of the wire. On your wiring diagrams, doesn’t it show the fusible links?