M620 M621 FAQ thread and registry

[70bus]

I was gonna title this “I am Joe’s M620 / M621” but I didn’t know if anyone else spent a bored pre-internet childhood at Grandma’s with only a stack of Reader’s Digest for fun.
At least “I am Joe’s pancreas” and such taught me more biology than my elementary school did…

Understand that I am no expert on this, and info here is based on reading books, hundreds of vintagebus and thesamba posts, my own experiences and conversations and emails with other owners far more knowledgeable than I. I have no ego on this and will happily correct/retract any information shown to be erroneous. Thanks to EverettB, hazetguy and notchboy for some proofreading.

From the prototypes in 1950 to July 1966, VW buses of all stripes were manufactured with a six volt (6v) electrical system as standard. However, as early as 1960, some models such as ambulance and fire truck were given twelve volts (12v) to handle a larger electrical load; other vehicles could also be ordered with this option. The M-Code for a 12v system is

M620 - 12v system (standard from August, 1966)

That wording has confused some folks; it simply means that 12v is standard FROM August 66 on, obviating the need for this option code on those buses. 620 is usually paired with

M621 - 12v warning light relay. - Except ambulances

621 is for an emergency-flasher system, i.e. hazards. European buses did not require the hazard circuit on 63 - 65 but in the US this circuit came in both 6 and 12 volt buses. The assumption one could make about the 'except' note is that since Ambulances have a different circuit controlling the rotating lights, etc., VW thought those made hazards redundant.

M620/M621 are also binned under some ‘package’ MCodes which contain other options;
M430 - North American export package including M20, M24, M25, M90, M175, M620, M621
is the most common one. However, Clara Williams states that this combo does not include M620/621 in 1965. My early-May 65 singlecab has M426 - North American export package including ? Includes 1500cc engine with the 12v codes called out separately. EverettB states “A lot of times the combination M-codes include everything that was possible, even in later years.” A system that obviously saves space on a small metal plate!

A factory-12v bus should have a red and silver sticker on the dash by the upper driver door hinge

If you have the original engine, the fan housing could also have a stencil indicating this voltage

This alerted production-line workers to install proper parts on the engine; stencils appear on some generators as well. Numerous M-code stencils appear on Beetle and Thing fan shrouds, including M610 (12v T1 system) but I did not find any images of a bus motor with 620 or 621; this could be due to these stencils being placed mainly on rear of shroud.

If you have a M-code plate with 620/621, this is a list of the equipment you should have:

EDIT: that list, although it is from a factory manual I have, looked a bit off; for one, it claims the 'emergency flasher' is 211 953 191A, but the parts manual lists it as 211 953 207. There is also a bit more info in the parts book, so... pardon the crappy paste-up job.

Images of these parts are here:
https://www.thesamba.com/vw/forum/viewtopic.php?t=779462
If you have images of any of the items on the parts manual list, please post them there!

All your lights should be 12v versions, of course.

Battery - obviously you should have a 12v battery; this is larger than the 6v and required a larger cover and strap as well.

Starter - many appear to have been a 6v starter and solenoid rewound for 12v, Bosch 0001208006 12V08PS. Starters have 6v teeth, and flywheels are 6v size (180mm). I have seen statements that a 12v starter was used and run with a 6v f/w that had 12v teeth. A definitive answer on that would be appreciated.

Generators appear to have been 6v sized but wound for 12v. 12v regulator - placement varies? Mine is on flat side of tire well.

Wiper motors are ONE speed. 1965 buses up the hard-to-find ante with one-year-only motor and yoke; this motor has a self-parking feature. May also have ignition-noise suppression. If you have a 620/621 bus and it has 2-speed wipers and/or an extra hole in the dash by the gas gauge, those are not stock.

Gas gauge - Clara Williams and Ryan Ousely both state they have seen 12v gas gauges stamped 1961. The earliest example I have found on thesamba was 9/66; i.e. the model year VW switched to 12 volts as stock. The small sample of pre-66 12v models means either these gauges all failed and have been replaced, or VW simply tossed 6v gauges in most 620 buses and hoped they didn't burn out. They also may have placed a resistor in the circuit to drop voltage, as apparently was done on some very early baywindows with 6v gauges. In any case, if you have a 620/621, check your gauge's backside for me!


Turn signals and emergency flashers - this circuit can be a real pain. Be glad if you do not have the e-flashers! Original turn signal flasher relay is a metal can suspended to left of fuse box (on LHD); it MUST have a KBL terminal for the circuit to work properly. Not 49a. Not P. … KBL. Due to the way the indicator light in the speedometer is wired, you can NOT use modern cubes usually sold for turn signals and have your bus work properly. OG relay cans were originally grounded through the post suspending them from the frame.

I have never seen a 12v version of this can; luckily, you can run early bay window units which have the proper terminals, plus a ground.

IMPORTANT - if you want to run a 215c box and find the speedo indicator is still balky or have slow flashers, try this unit
https://www.pantera-electronics.com/signal%20flasher.htm

This can fit in a Hella 215c box and possibly others to hide it. It will ALSO allow you to use LED lights with no further modifications.

The emergency-flasher relay is a dead ringer for the later hi/lo headlight beam relays, and to make matters more confusing lives in the same spot.

(image courtesy pedro sainz. )
Finding this 12v relay can is nigh impossible. They are also used on Type34s for a passing feature on the fog lights. Modern cubes are available to replace this relay; they need to have 87 and 87b.

To complete the parts for this circuit, you will have an e-flasher switch and a dash indicator light

This switch DOES NOT light up.

This light above the wiper switch does.

Knobs on the emergency circuit switch should be red, with writing, but a few folks with early buses reported plain black. This switch connects all four terminals together when pulled, same as some wiper switches of the era.

When connected properly with correct parts, your hazards work with key off, and as BarryL says “Also you know you got it wired correct when you pull up to park with your turn signal on and keep your foot on the brake and turn off the ignition and the bus goes run-off-run-off-run-off until you let up the brake.” That goes for 6v e-flasher buses as well BTW. I'm working on a post to combine all those 'my flashers don't work' posts but it may be a while.

Many 12v cars are commercial vehicles or trucks, with a smattering of Deluxes and other high-end models. Digging through the forums, there are roughly 40 factory-12v buses either owned by a thesamba member or mentioned by one; not rare, but not common. The bulk seem to be from 1965.

I made a list of all members who stated they owned one, but time passes and buses move around; if you are currently one of these lucky owners, please post up your bus and the M-Codes and use this post as a registry. If you have photos of any of the parts on the 620 list, please put them in the 'parts image' thread as well.
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Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[Lind]

[70bus]

My M620/M621 1965 single cab

06 4

426 002 043 071 620 621

UO 2612 131383 5148182

002 With US specific USA: Sealed beam headlights and pre-heat flap delete (?)
043 Complies with Swiss market regulations
071 Second locker hatch for single cab pick-up
426 North American export package including? Includes 1500cc engine
620 12v system (standard from August, 1966)
621 12v warning light relay

Delivered to New Orleans. Pearl white with mesh grey seats; had grey shifter and dash knobs, ebrake cover and shifter boot as well.


"birth certificate" from factory states production of
'Built on 05.05.65 left factory on 11.05.65' (Euro dates), so built in six days starting May 5, 1965. Yes, the Mplate says 4; I remember dabating that with Clara decades ago, but the chassis, transmission, and front horn numbers ALL line up with a post-May 1st production figures so either the plate is a typo or they made the plate and it sat before they started the frame.

Chassis 148182
front axle 1436042
transmission H782 7701
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[scvw]

I have a very original 27/5/63 Ruby Red SC that is factory 12V. It still has its factory engine and all the electrical bits. I will try and post some pics soon.
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58 Coral Red ragtop(Diana's car)
63 Ruby Red SC
67 Pearl White SO42
SOUTHERN INTEGRITY AIRCOOLERS

[scvw]

Here is the mcode for my ‘63 SC.

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58 Coral Red ragtop(Diana's car)
63 Ruby Red SC
67 Pearl White SO42
SOUTHERN INTEGRITY AIRCOOLERS

[scvw]

As you can see the 12V sticker is much larger then the later ones.

_________________
58 Coral Red ragtop(Diana's car)
63 Ruby Red SC
67 Pearl White SO42
SOUTHERN INTEGRITY AIRCOOLERS

[70bus]

Thanks to Lutz at ClassicCult I finally have a correct emergency flasher relay, 211953207.

Working like a champ! As an aside, he has others, and not all of them are marked "12 Volt" but all had proper part number. Yes, the right cube or an equivalent VW relay works, but i am a weirdo and want the 'correct' part.

I am STILL looking for the actual can for turn signals used in these buses. Almost every one I've seen has been for post-66 buses; i.e. has the 49+ terminal and no KBL. Factory parts listings contradict themselves somewhat (211693191A and 211953207 both listed as eflashers), and they are often listing the post-65 parts. I suspect the original part # is a 111 rather than 211. It's not in Progreive Refinements, but somewhere out there is a tech bulletin describing the 'new' e-flasher system with contemporaneous part #s or a good pic of the can. I'd love to get a Bosch number as well.
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[70bus]

Some of the parts listed in the parts catalogs above have turned out to be from later buses; as many of these manuals were printed after 12v had become standard, there are 9-pin-box bus electrical parts and other bits that would not be correct (or sometimes work) on an M620/M621 bus. I was able to find a legible parts manual supplement (3/64) which lists all the new parts VW was using for 63-up US spec bus with emergency flashers and 12 volts:

These are what came on the bus; some 'superseded' parts lists update some of these parts with bus-specific numbers (211 as opposed to 113, etc) , but many appear to simply show when the 9-pin stuff becomes standard.
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[tasb]

This is the M code plate on my 1965 Hardtop Deluxe. I have owned this Bus since 1990. I purchased it in Apple Valley, California for $340 down from $400 because it was only running on 3 cylinders.

During my ownership it has undergone three restorations and has been driven extensively during that time. Much of the time it was a daily driver. I have no idea on it's actual mileage but it is likely in the 300,000 range.

Because of the length of my ownership and how much it has been used I have very little left of the M620/621 bits and pieces. I had no idea it is a rare Bus until recently. So, as it was restored and as parts wore out they were simply replaced. At one point I wanted to clean up the M code plate so I tried removing it. The screws didn't loosen it from the bulkhead so there it remains.

The battery cover featured above is one part that I still have. I thought that the two speed wiper switch was an owner "upgrade" so at one point I removed it, filled the dash hole and installed a single speed switch in the still existing dash hole. I do still have the multi speed switch and the two speed wiper motor is still in use running as a single speed.


UH= delivery to Houston, Texas
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Roads Scholar
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

Member# 2059

[70bus]

How had they shoehorned the 2-speed wiper in? My truck had original switch and also had a 2-speed switch - screwed onto the tray - but no motor; the 65-only wiper assembly did have the U section bent nearly closed, which I guess is how the got the bigger motor in.
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[nlorntson]

[70bus]

Thanks for pointing out an assumption on my part - I was thinking of just 63-65 buses, and forgot 66 introduced some changes. Wipers are indeed single-speed up to Aug 1 65; however, progressive refinements states 2-speed motors are fitted starting Aug 2 65, chassis 216 000 001. So you and other 66 owners did come with that 2-speed motor and switch.
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[stevo]

Here comes another factory 12V bus. Mine is an April 1965 Standard.
It has a two-speed wiper motor, it's switch held with an escutcheon and self-parks. Has the emergency flashers using its original relay; still working on getting all relays happy with hopes the flashers will work properly. This bus was a fairly simple standard with two pop outs, no entry port on the M-code plate. Original engine long gone. When it came to me 15 years ago it had an unknown dual port which is still going strong- unafraid to drive anywhere. Upgrades I've installed are modern Bilstein shocks, two jalousie camping windows replaced pop-outs, 15" rims, early bay Westy bed, and full width middle seat. In 2000 it was totaled in a natural disaster, but since I adored this bus and the way it came to me I chose to keep it going. During the repair factory safaris, sunroof assembly and belly pans were installed. After repairs an NOS 2101D Philips auto mignon 45 rpm record player was fit under the dash.

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When you cross an Irishman, they never forget. I mean, never.

[70bus]

Post up your transaxle, front beam, steering box, and any other serial numbers you can find to pin down production rates. My bus has 06 4 as a date code, yet 'birth certificate' says early May - and so do all the production numbers. So my bus is either 2 weeks before or two week after yours...

Looking at your plate, your bus is 6,534 buses before mine, so about 3200 buses a week, or over 500 a day that spring.
_________________
Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[tasb]

I had the fan shroud ink stamps reproduced.

12v above generator and M620 beside the coil.
_________________
Roads Scholar
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

Member# 2059