Alternator wiring

[vdubeetle]

Hi all well like it says im having trouble wiring my alternator. been looking at wiring diagrams and all of them have an external regulator that they hook up to but my car,68, doesnt have one so im guessing it is internally regulated? i have circled in the picture the wire i need to hook up. on the black base it says D+. Do i hook it up directly to the battery or somewhere else?

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will you loosen up or will I have to take out the persuader(sledgehammer)

[mrbigmax]

If you can make a cup-o-soup, you can wire an alternator. Follow these simple directions:
http://www.chircoestore.com/catalog/product_info.php?products_id=4517

If this is a new conversion, make sure you have clearance between the alternator and the accelerator pump linkage on the carburetor.

[vdubeetle]

Thnx for the link question though if i dont have that idiot light can i subsitute it with something else?
And the PO bent the accelerator pump linkage slightly so that it doesnt rub on the alternator is this bad? I dont have any issues with the car.
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will you loosen up or will I have to take out the persuader(sledgehammer)

[ashman40]

Your alternator is an INTERNALLY regulated alternator (AL82). The D+ terminal needs to be wired to a 12v+ source for two reasons:

1) Prior to starting the 12v+ input into the D+ terminal will build a magnetic field which will start the alternator charging. Without this input to initially build the magnetic field, the alternator will spin but not build current. Once charging, the alternator will "self excite" itself and keep itself charging.

2) While charging, the voltage coming in on this circuit is used by the voltage regulator as a reference to control the charge rate of the alternator.

You could use a 12v/2W lamp in the D+ circuit in place of the Gen light in the speedo. This circuit, with bulb, is needed to get the alternator properly charging. Do NOT use an LED since it will have much lower resistance.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[vdubeetle]

Thnx for the info is this same wire connected to the gen light on the speedo? My generator light isnt working
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will you loosen up or will I have to take out the persuader(sledgehammer)

[ashman40]

[vindeisel93]

I used this wiring guide on my 68 bug about 1 month ago.

They gave it to me when I bought my Alternator at the local vw parts store here you go! Alternators are internally regulated as well. So you'll have to disconnect your old voltage regulator that your generator used and re some items under your back seat using this guide.

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1968 Type 1 Bug
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Cheers,
Matt

[68IHscout]

[barry cox]

I converted over to an Alternator when I put my new engine in. My problem is this. I cannot get over 12 volts on my voltmeter if I leave the D+ wire on the idiot light. I can however get full charge to 14.2volts if I run it by the ignition switch. But you cannot stop the engine like that. You have to pull the coil wire off the fuse box. I reran a new solid wire from D+ to the idiot light on the speedo, but it still stayed around 12v. I put a test light on the D+ end with the key on and it shows a low glow. Does that mean I have a bad speedo head, because the hot wire to the 3 lights goes directly to the #1-2 terminal on the fuse box?

[vindeisel93]

Oddly enough I have the same issue except my charging system is working. When I take a multi-meter to my battery it shows 12 volts. My battery is a year and a half old and I've been using my new alternator with the wiring from that diagram the entire time.

It appears to be that my charging system is working and just not showing it on a mulit-meter. My bug is my daily driver and I've had no problems with it whatsoever. I don't know what to tell you to solve your problem. I'd just like to say I've got the same issue and it has given me no problems with my car dying or having a flat battery.

Perhaps you should try giving it a couple days driving with the issue you've explained and see if the battery starts to deteriorate.
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1968 Type 1 Bug
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Cheers,
Matt

[barry cox]

Thanks for the feedback. But what bothers me, is this. That the VW machanic I have talked to here in Mobile says the test light should fully light up when put to the D+ terminal. My test light just has the low glow like the idiot lights do on the speedo head, and not a bright 12v glow. I guess I should purchase a hand held volt meter to check the D+ wire. The stock gen-light is not going out when you accelerate the engine. It has a constant low glow as well.

[ashman40]

[barry cox]

Thanks, I will try all of this.

[Aircooled Barry]

Ashman40 thanks for the tips. I have a 69 beetle that someone put an alternator into with external regulator but it is not charging the battery. Idiot light works but only two volts running back on the blue/green wire at alternator. I wondered if my turn signal indicator light being out is then related to my alternator problem. Probably not but I will test everything as you recommend. Amazingly the PO had wired the red lead from the voltage regulator straight to the + coil terminal. With nothing on the d+ terminal. Although it was charging the battery the alternator was getting very hot. Well I pulled that connection off the coil knowing it didn't look right. Unfortunately I had driven the car for several months like that not knowing it existed. Just FYI in case someone else comes across a similar problem. I have other drivability issues that I think are electrical so I'm afraid I may have damaged the coil, regulator, or alternator. But I'm excited to do your series of tests.

[ashman40]

[Aircooled Barry]

ashman40 you are a wise man. I will try to answer your questions. The voltage regulator(VR) is external bolted to the fan shroud similar to the ones you posted and is not original. It has a red wire coming out the bottom and a bolt and nut on the face of it. It is shiny chrome without a brand label and embossed in the metal it says "neg grd". So I pulled the red wire off the coil and looped it into the d+ wire going to the idiot light which now lights at all times. The bolt and nut on the face of the VR has the wire going to the alternator DF. And there is one other wire off the alternator D- going to ground on the fan shroud right next to the VR. The original VR is missing and under the rear seat looks like a head light relay with three wires connected. I will retest the voltage on the blue wire.
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1976 Westfalia, 1980 Porsche 911sc

[ashman40]

[Aircooled Barry]

Ok I posted two pictures of my alt and volt reg in the forum area. I hope you can find them. Under the title of "alt wiring on 69 bug" under my user name. Technology can be difficult. But .. I left my key on last night to test my coil and after abou 30 min it heated up until I could not keep my hand on it for more than 15 seconds. I discovered I do need a new voltmeter that reads tiny ohms but I suspect the coil is ruined. The ohms on the two terminals are 4.2 when hot and I need a new meter to read the center connection. I don't think it should heat up like that. Suprisingly it still started but would not idle. Also suspect is the VR. I don't know how they work or how they are tested. Thank you for all you help. It's amazing to me to be helped by a person from Tokyo. I did live in Japan for a summer and loved it!
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1976 Westfalia, 1980 Porsche 911sc

[george4888]

Leaving the key in the ON position overnight will probably burn up the coil or fry the points. I cannot think of a logical reason you would want to do this, other than to see how long your parts might last. Follow the good advice from the smart man in Japan. His wiring and pictures of the alternator is right on the money and he really did a great job of explain how the wiring goes and to where. If you see only 12 volts , at the battery post, when using a volt meter, your charging system is not working. Charging volts, measured at the battery should read between 13 and 14 volts. That is with the engine running and alternator working. The turn signal light has no affect on the charge idiot light on the speedometer. But, that "idiot" light has to be connected and IN LINE to the alternator or the alternator will not work properly. The "light" acts like a switch to provide 12 volts to the field of the alternator. !2 Volts to the field and when the engine is running, you have 12 plus volts going back to the light bulb, causing it to shut off, so to speak. So, the light in the speedometer is required for the alternators to work. Don't leave the key in the ON position unless the engine is running . You could run down your battery, doing that overnight with the engine OFF. Not a good test idea or concept.
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Home of Karacostas Car ( VW) Repair
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Past NHRA and IHRA drag racer
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1969 Beetle, 2007cc engine

"Life is hard, but it's harder when you are stupid."

[ashman40]