Pin arrangement is slightly different between the two switches.

On May 27, 2012, at 10:11 AM, Loren Busch 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.