So...I let the ol lady drive my work van, she left the lights on, killed the battery, then hooked up the jumper cables backwards. Though Ive figured out what to do about the ol lady, I cant get this doggone van back up and Im missing way too much work. Literally breaking me...
So...
I get the van back and besides not charging all appears well. Changed the alternator...
Still not charging. Changed the voltage regulator... Now the battery gauge pegs and the voltmeter says the battery is holding 14 volts. The gauge pegs with the key on, but the engine off. And when the engine is running the VR gets hot fairly quickly, and over charges like a dentist with a coke habit. Im not sure if it is any good or not now, and I've no idea how to test a VR. I would think there was a direct short caused by melting wire insulation allowing a "key on -hot" wire to touch ground, but can see no such thing anywhere, under the hood, in the dash/cluster area, or anywhere else. I read a post titled "voltage regulator problems" where the gentleman instructs the other to re-wire slightly,and temporarily in such a way that would effectively bypass the battery gauge and allow the engine to charge. At the time this sounded worth a try, so i did. No dice.
If I disconnect the battery gauge wire at the VR, the engine will run, but wont charge, and nothing seems to be shorting out. And if I run or even just turn on the ignition circuit with that same wire connected, it gets hot ( enough to start smoking after about 15 sec.) at the VR wire that connects to the "key on hot".
So if there was a direct short somewhere in the ign. circuit shouldnt it still short with the gauge wire disconnected?
And if the short was something on the battery gauge wiring, shouldnt that be the one getting hot? And I would also tend to think that it would not charge rather than over charge. I dont know much about how the coil, resistor, or module would/could play into this, so Ive left them alone so far.
Im about to go outside and stare at the wires till something comes to me. Since I cant go to work. (Im told stupid is a permanent condition... ..so...theres little chance of ever fixing the ol lady...legally anyhow)so I have nothing better to do but try. I could sure use some educated advice (on the electrical issue) before I screw it up worse.
Maybe I can install a dummy light on her...nah ! I couldnt afford that electric bill. ( this looks just like her! ) LOL.

 

The most common result of reversing the polarity applied to the vehicle is a blown diode in the alternator. Diodes usually blow open, so this doesn't necessarily cause a short - it just prevents the alternator from charging. This would explain the first problem you had (not charging) and it makes sense that you'd change the alternator. I follow you so far.

Then you changed the voltage regulator, and things went south. When you mention the battery gauge, is that the ammeter in the dash (that says D and C)? When it pegs, which way does it peg? When you say the system is overcharging, how are you determining it's overcharging? Does that mean you're measuring the voltage across the battery and it's very high? If so, what is it? You said earlier that the battery voltage is 14 volts, but the system is overcharging - are these different times, or what's going on?

Please be more specific about what's happening (use concrete, objective terms). Also note that any "extra" wiring you do or changes you make beyond the factory setup is going to make it even harder to solve over the internet.

 

1. "Is that the ammeter in the dash (that says D and C)?".............yes it is.
2. "When it pegs, which way does it peg?"..................................towards the c.
3."When you say the system is overcharging, how are you determining it's overcharging?" The battery needed to be jumped it was so low. After I had started it. I was going to grab my multi meter when i noticed that lovely aroma associated with shorted/burning electrical equipt./wires. I had jumped out front to verify this and saw smoke coming from the voltmeter. Immediately i yanked the battery cable ( before now it wouldnt run without the battery ,so i had no reason to believe it wouldnt kill the motor and stop the smoking at the same time. It kept running. This all happened in about 20 seconds. After i shut it down i checked the voltage across the battery.this is when it read 14.5 i think it was. so to answer your question... i guess im assuming it was overcharging based on the ammeter and thew samoke and the voltage increase from 10.something to 14.5 in 20 seconds. this seems rather quick to me. what i found today was that i could unpeg the gauge when disconnecting a heavy gauge white? wire. hard to say maybe its tan.Anyway it was from thje back of the ign. switch to the fuse panel. i post exactly which circuit later tonight.the wiring to the best of my knowledge...unaltered with the exeption of the lighting system. The ignition system remains as its been working well for years until it was jumped backwards. The re-wiring i did was supposed to be a temporary bypass of the ammeter. it didnt work, i put it all back the way it was and purchased a new VR and installed it today. thanks a ton for your time. let me know if theres any other info you need. or something i need to check or photograph and itll be done promptly as i am stranded, 2 weeks out of work from no vehicle and going down in flames. so your help is appreciated more than i am able to express. (if youve ever got some plumbing advice issues...im your man. hit me up. thx again. looking forward to your next reply!

 

sorry i said smoke coming from volt meter... wrong. i meant voltage regulator.sorry

 

Okay, I think there may be a reasonable explanation for what you're seeing. When your wife hooked the jumper cables up backwards, this reverse polarity would have caused excess current to flow backwards through at least one diode in the alternator. This probably also blew the fusible link that protects the output of the alternator. If this happens, the alternator is effectively disconnected from the battery.

If THAT happens, the alternator output can climb sky high no matter what the voltage regulator does because there's nothing left to sink current from the alternator. In this case, the only load on the uncontrolled alternator is the input to the voltage regulator, which will sink too much current. Since excess forward current would then flow from the alternator into the voltage regulator sense input through the alternator feed AND the ammeter shunt, this would explain why your ammeter is pegging toward CHARGE even though the battery voltage isn't sky high. It would also explain why your voltage regulator is cooking.

To verify this, disconnect the negative battery cable, and measure the continuity between the BAT stud of the alternator and the battery side of the starter solenoid. If the circuit is open, replace the fusible link, and replace the voltage regulator since it's likely cooked. Also look for any burnt wiring that might have occurred in the process. Then try again.

The only things I can't explain are why your battery is at 14.5 volts (that's usually a healthy charging voltage; if the battery were completely cut off from the alternator because of a blown fusible link as I suspect, the battery would read around 12 volts). It's also not completely clear why disconnecting a wire from the ignition switch has anything to do with the issue. Either way, check the fusible link for continuity first as that's an important first step.

 

thx again , i will go try that in a minute and post my findings shortly thereafter...