Just some info on what could be a head scratching problem and how I'm fixing it, and how I'm diagnosing, since I see a lot of charging issues discussed. car's a 1970 Skylark cloned to a GS455. Original wiring harness that was removed and checked by me. May have issues with the harness now, read on This is just general info for the group, I've got a handle on it. I have a bad alternator and possibly a bad harness now. I have to do more tests OK, so I had to replace the voltage regulator in my car. Just some background if you haven't been following: GEN light wouldn't come on with key ON, but would come on (1/2 bright) with key at ACC. Battery wouldn't charge over 12.5v, and will drop once it gets there. I had 13.7 at one point, but it immediately dropped like stone as I watched the meter. normal voltage at the battery while running on this car has always been about 14.2v. Normal range according to Buick is 13.5v to 14.5v. With all electrical systems running, I used to see just over 13v. Now with everything on I am seeing about 11.5v-12v Got a NAPA regulator for my 62A system. Part number VR146. Made in USA, not a solid state circuit board; it's the two relay type. Nice part, 54 dollars plus tax. Made for NAPA by Echlin. bar code reads R720816 the one it replaced IS solid state, and that one has a burned out 100 ohm resistor- at the #4 terminal. #4 terminal and the F terminal scorched This #4 terminal waits for the #3 to supply it with voltage. When the #3 closes the circuit, the voltage at #4 is the same as at the #3, shutting off the dash light. This is why the GEN light should be half bright with the key ON, but off with the key OFF and full off when the engine is running But also, the #4 is connected to the F terminal, which goes to the alternator. On inspection, the F connector inside the alternator is also scorched Fine. New regulator is installed So now, the GEN comes on full bright with the key ON, when it should only show 1/2 bright (because the #4 isn't getting full voltage from the #3 at that point, one side of the bulb sees 12v and one side sees ~7v, making for half voltage across the light, making the light show half bright) and the light doesn't shine when the key is at ACC- which it should be here's the catch(es): Connector at the volatge regulator is melted through on the F connector. Wire is still good, I checked continuity- but I checked it cold. might have infinite resistance hot, I forgot to check I haven't worked it all out in my head yet, but here's where I am: Old regulator giving full voltage to #4 connector at all times. That's why the light was off. #4 is also connected to the F connector which goes to alternator. Resistor on the #4 in the regulator overloads and burns out (I believ it's a 100ohm resistor). What it does when it burns out...is what I haven't worked out. But it was hot enough to melt the plastic gang connector The alternator is probably shot. Battery is now at 12.08v at rest. Given that the regulator is physically badly scorched at the spade terminals for the F and #4, and the circuit board is burned at the #4 right over the resistor (still smells bad, too, I knew it let the smoke out while I was opening it), and that the F goes directly to the alternator AND that the alternator is scorched at it's own F hole...the alternator couldn't be good. But what does the light off at ACC mean, I wonder? And why full bright with key ON? I have to study the manuals again. I think what this means (and my suspicions have been so far been borne out on this) is that in ACC, the key gets power from the battery, and a signal from the alternator (Through the F connector to the #4, inside the regulator) and that since the electrical systm works when the key is in ACC, the light just doesn't come, that the alternator is just passing a full 12v on to the #4 via the F connector, and since the light gets 12v from the hot side and now is getting 12v from the charging side (alternator's not doing anything with the volatge), the light is constantly off I have to turn that theory over in my head some more. I haven't worked out how the alternator does it's thing yet. I now about the description, but I can't walk myslef through it in my head yet. I know why the alternator does it's thing, i just have to study the alternator more. But my hunch feels right, especially becaise the GEN light is full bright with the key ON I'll let you know what I find. The GEN light in these cars tells you quite a bit if you know how to interpret it :TU: PS Did all that info confuse you or what? Now you know how I feel poring over these diagrams and manuals all morning :laugh:
Alternator tests as bad as well. Hopefully the wring is OK, haven't had a chance to check hot, and obviously that has to wait NAPA can order a correct "61" amp alternator (although mine plainly reads "62A" on the housing this is the best they can do), so mine should be in tomorrow Bonus at NAPA: they can bring up a digital photo of the part on their PCs. I could visually verify that the "F" connector hole is 'clocked' correctly for a Buick- sometimes you'll find that they are positioned so that you can't plug in the connector. This one should be good to go, no fuss no muss. 55 dollars and change
Chris have you had your guages unhooked on the back side? Meaning the main plug that goes on the pins on the back side of the guage. I had a similar problems and it turned out to be one of the connectors in the plug had gotten pushed out when I plugged it back on the gauge. Fought it for a long while, replaced alternator and reg and still had the same problem, the light was bright when engine ran and never went out. Pushed the wire on the plug while car was running and the light went out. Never was so happy in my life. Hope this helps. Rick
Chris, I told you in your other thread that I had a feeling it might be the alternator. I had the same problem man. I hope it turns out to be a fruitful purchase. We ALL hate to have to deal with the dreaded harness.
Yes, I know Ken. But you see, the alternator didn't make the regulator go bad. The regulator is burned. Replacing the alternator wouldn't have fixed the burned out 100 ohm resistor in the regulator. I'll post a pic of the regulator tomorrow; it's at work replacing the forward harness isn't that bad. I've had both the main dash harness and the forward harness out, chasing down a short, about 5 years ago, so I could check resistance on everything Getting my starter motor out to replace those wires...now that's the problem. Tight fit with the extra thick heat shield and headers. I should have replaced it 5 years ago when I did my fusible links over but I didn't have the money. It ended up being a bad ground wire to a headlight the whole time ou: It was like Greg brady's car, remember when he fixed up his car, and when he hit the horn the windsheild wipers came on? It was almost that ridiculous.
Thanks. The light was doing exactly what I expect with a bad regulator however. With the burned out regulator, the light was off with the key ON. Honestly, this happens when the voltage at the #3 terminal is provided to the #4 terminal. Since both have the same volatge, the light goes out. On the burned out solid state baord, the resistor is fried. Board is burned brown there, and it got so hot it discolored the metal housing. The light was off with the key ON which means the same voltage is at #3 and #4, and the light was 1/2 bright in ACC. The regulator was always supplying full voltage to the #4, which also is wired to the F wire that goes to the alternator. I'm looking at the Buick manual's diagram right now the connectors on the regulator for the 4 and the F are also scorched With the new regulator, the light comes on full bright before the engine is started which is incorrect, and in ACC the light is off. The alternator is incapable of charging the battery fully and an inspection and test revealed scorch marks on the F connector of the alternator the light full bright means that 12 volts is coming in one side of the light and zero is coming in the other. if i have to, I will test the new regulator, but I will install the new alternator first, since that is also definitely bad. The problem could be the wiring just isn't allowing the #4 wire to carry half voltage back to the light anymore like it should with the key ON. instead it's carrying nothing so the light is on full bright. With the light off in ACC, I am a little worried The light is functioning properly. The system isn't I appreciate the input truly. I wish folks wouldn't take this stuff I'm typing up the wrong way, but I really do thank you for the help. It's just that this suggestion isn't the problem. the regulator needs to get the correct volatge to regulate and the alternator isn't supplying it The regulator told the alternator to screw up. The alternator followed orders and the regulator commited suicide by immolation. Hopefully it didn't kill the wires, too :laugh: Fusible links are still good, and they are only 5 years old or so, I re-did them recently, so I have hope the harness will really be OK But for-real, I'm not just throwing new parts at an electrical problem I've tested it the way the manual asks me to I'm relating what happened and how I'm addressing it as info for the group
here's the Regulator. You can see the resistor, barely, under the brown/black part. Also note the discolered plate underneath. This thing got hot I'm not surprised the alternator is bad, too after seeing this. What you can't see is the burn marks on the F terminal and 4 terminal connectors. NAPA had one, it's ordered, will post a number. 54 dollars and change, no core charge
I forgot to bring the part # ou: Anway- now the regulator is working fine. Alternator is providing voltage. Light is bright at ON and now turns 1/2 bright as engine starts, goes out when engine is running I learned a few things about the mechanical regulator- you can fool the car into thinking the key is turned to start by pressing the #3 points and you can also simulate the engine running as far as voltage to the instrument panel by pressing the #4 points. Don't ground them while doing it- it will ruin the regulator by the way battery is still 11.6 volts at rest and will only charge to 12.75v. I'll do a battery load test when I get a chance
