internal regulator or external.

[jetmech]

As I do more research for my electrical harness I was looking at my alternator the part # is 120 400 836, when I look it up online is says its an internally regulated alternator, but when I was pulling out the rear seat I found what looks like a regulator and the wires are routed to the engine compartment and are connecting to the alternator, I've included a picture of the alternator and the regulator under the seat. So do I have an internal or external regulated alternator?

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74' Super Beetle

[glutamodo]

Whenever you have a three wire plug on top of the alternator, it is externally regulated. And yes, VW number 043 903 023A part number is a Bosch externally regulated unit.
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Andy T.

"What is Glutamodo, Horror of Toyko, besides total, fiendish, quality-a-you brain!"

[sjbartnik]

Yes it is external. Surprising to see a Bosch, I thought all the external-regulated ones were Motorola. I guess not all.
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[glutamodo]

I've previously quoted one of the VW "Bibles" - the J.T. Garwood, Car of the Century book, in previous thread. It seemed to indicate that Bosch Alternators went with Bosch regulators and likewise with Motorola.

[Danwvw]

I haven't seen one of those in a beetle usually the external VR Alternators here in the US are Motorola. I think it can use a generic VR the Motorola does. Probably find one at the local auto parts store. https://www.rockauto.com/en/catalog/volkswagen,197...lator,4884 As for the cable I would think it's going to have to be a used one someone could have or just use spade lugs you could move it to inside the engine compartment.
From the looks of things the a lug inside the connector caught fire and for that to happen I would think the Alternator burned out too. New Alternators will have internal regulators and you won't need that cable. Well unless you find a rebuilt one like your alternator.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[ashman40]

Be careful as you look up part#s. AL-78 (or AL78X) is a common generic reference for the external regulated alternator. AL-82 (or AL82X) is commonly used for internally regulated alternators. But then you see references where they are used interchangeably. This could be because the AL-82 superseded the earlier AL-78 as a replacement part. It saved on the need to stock the extra external VR as part. You can install an AL-82 alternator in place of an AL-78 with just some simple re-wiring (splice two wires together). But an AL-78 cannot replace an AL-82 without also adding the external VR and all its wiring. Because the AL-82 was used in more model years they tend to be easier to find and often cost less. The FLAPS near me can order both but the AL-78 takes longer to get.
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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!}

[jetmech]

Currently the alternator is working fine with the regulator that is installed from what I can tell; I recently removed the battery and placed it on a charger for a few days, because the car is sitting on blocks while I work on other things. I reinstalled it yesterday to start working on the engine, checking the timing and other overall checks which included checking the voltage of the battery with the engine running and I was reading about 14.3 volts, so the alternator is giving a charge to the battery.

So with my searching around the car of what is installed and what I want to add to the car, I have determined that I will be going with a modern fuse box that will give me the space for expansion to include seat heaters and a 5-8 Kw diesel heater.

I assume that the regulator must be kept from the weather instead of being placed in the engine bay closer to the alternator?

Thank you all for the input about the regulator.
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74' Super Beetle

[Glenn]

[60ragtop]

yes BOSCH and MOTOROLA had different wiring for the external VR. You could get an adopter to fit one or the other. I have one in my stash I think.
https://www.thesamba.com/vw/forum/album_page.php?pic_id=732312
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Rick
Certified Mechanic by the State of Michigan in 1977
ASA certified in 1987
Certified Hunter Wheel Alignment Master Technician 1986

[volksworld]

the original motorola regulator you have pictured was a sealed electronic unit and shouldnt be adversely affected by mounting in the engine compartment but of course the plug isnt sealed and could be subject to corrosion....ghias and buses had their regulators in the engine compartment...6v cars sat them on top of the generator and i've seen plenty of 12 v conversions with the regulator screwed to the fan housing....i think the back seat location was done more for space limitations in the engine compartment than for weatherproofing

[Glenn]

My Bosch alternator has a Motorola regulator. It's been that way since 1974 when I bought it new.
_________________
Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

Member #1009

#BlueSquare

עַם יִשְׂרָאֵל חַי

[TK-CS]

[Xevin]

Maybe this will help somebody in the future. This is the current external VR used for my 74 bug with a Bosch Alternator

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Keep on Busin'

[ashman40]

Here's an old post about someone trying to get a US-spec Ford VR to work in place of the VW VR.... it apparently worked:
https://www.thesamba.com/vw/forum/viewtopic.php?t=573162
Conceptually the VR works the same so in a pinch you may be able to use a VR-166 part# from any US FLAPS as the VR for your Bosch or Motorola AL-78 alternator. I've not tested this myself so YMMV.
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AshMan40
---------------------------
'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!}

[Danwvw]

The Motorola Alternators came in a couple of configurations one was with the regulator mounted to the outside of the Alternator. I think parts may be interchangeable between the two configurations.
VW and Dodge Jeep and Ford in the mid 70's used "B circuit" regulators. Where "A circuit" regulators regulated the Positive power feed to the Armature and "B circuit" regulators regulated power between the Armature and ground.

Motorola Alternators have the Diodes inside:

Motorola Alternator with Regulator attached:

Motorola Alternator that uses a separate mounted external regulator:

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[TK-CS]

[Danwvw]

I would think the attached regulator would be the way to go: Here is a Classified Search for Motorola Regulator. I have several 3 prong Motorola Alternators and some parts. Usually what goes wrong with the Motorola Alternators is one brush wears down and sometimes they melt an internal diode. The 3 prong connectors tend to get broken due to the fragile nature of the white ceramic they are made from.

Here, one of the diodes melted its solder and fell out.

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[TK-CS]

Hey Danwvw, thanks for the pictures and information.
I would like to keep the wiring unmodified. So I think I would need a brush holder and this cover with the 3-prong connector.

I looked at all US ACVW shops that I know. But I seems that these parts are nla. The Motorola alternators were never used in European cars, so no need to look over here for spare parts.

Perhaps I have to keep this alternator as it is and sell it and get another Bosch 3-prong alternator.
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AC:
'71 1600LE (Type 3 Notchback FI/AT) Sunroof
'75 1303 (Super Beetle) 1600DP, Sunroof
WC:
'77 Audi NSU Ro80
'88 GTI 16V
'91 Corrado G60
Daily:
'04 Passat Wagon 2.0TDI
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