I realize the question is aimed at Mark, but since I started all this.....   ;^)

Van Cafe shows that headlight switch with B or M suffix is ok for
Vanagons prior to the changeover to switch with T suffix.

PN with M suffix supersedes PN with B suffix.

Bus Depot shows the chassis number for changover to T suffix switch:

http://busdepot.com/view.jsp?model=43&category=13&group=86&prodgroup=711

GoWesty provides the serial number for changeover:

http://www.gowesty.com/ec_view_details.php?id=3249&category_id=&category_parent_id=

From Van-cafe website:

"Headlight Switch - Check description

251.941.531M

"This Headlight switch fits up to 1989 or 1990 Vanagons. The other
(251.941.531T) fits newer ones. If you have an 1989 or 1990 please
check part number of your part- Switches are very similar except for
the location of 1 pin connector. (If the old one has part number
251.941.531B, that one is now the 251.941.531M) "

Neil.

On Sun, May 27, 2012 at 7:11 AM, Loren Busch <starwagen@gmail.com> wrote:

> �RE: Headlight Switch Later Models
> Okay Mark, got that. �Now a follow on question. �Since it appears that a
> '90 �Vanagon could have either the B or M suffix switches originally (and
> corresponding wiring) but either will appear to work correctly (but no fuse
> in dash light circuit if B used where M should be) then how does an owner
> of a '90 Vanagon check to see which is correct? �This assumes that a PO may
> have put in a B where an M was originally. �How can you tell which is the
> correct switch?
> BTW I'm asking because I think I may have done exactly that some years
> back, put in a B when an M failed.

-- 
Neil n

65 kb image Myford Ready For Assembly �http://tinyurl.com/64sx4rp

'88 Slate Blue Westy to be named.

'81 VanaJetta 2.0 "Jaco" �http://tubaneil.googlepages.com/

Vanagon VAG Gas I4/VR Swap Google Group:

http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines