John, Mark is right, the later model vans (86-91) have to use the two
prong brake switches.  All the wiring diagrams call for them.  I would
buy the two prong switches and you will be good to go.

Ken Wilford
John 3:16
www.vanagain.com

On 10/18/2010 11:30 AM, John Rodgers wrote:
>  OK, so this raises a question. Can a three prong switch be used in
> lieu of a two prong switch?? Thus leaving one prong without a wire to
> it. Will the brake light system still work properly?
>
> What are the differences in the wring that a three prong switch would
> not work in place of a two prong switch.
>
> Thanks.
>
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com
>
>
> On 10/18/2010 7:58 AM, Ken Wilford wrote:
>>  Mark, I wish I could say that I have found what you have written to be
>> true.  I just dealt with this issue with a customer with an 87 Vanagon
>> and he had the three prong switches.  I would check before I ordered
>> because it seems more random than a specific year cut off.  It takes
>> about 5 mins to remove the instrument cluster and look at the switches.
>> Unplug one of them and see if the lights go out.  The switch that you
>> can unplug and it makes the lights go out is the bad switch.  The
>> switches are wired in parallel so that one of them is redundant.  If you
>> were really in a bind you could unplug the one and just travel the rest
>> of your trip home with just the one plugged in.  I would replace both
>> since they are both the same age.  I have the switches available if you
>> need them
>>
>> Ken Wilford
>> John 3:16
>> www.vanagain.com
>>
>>
>> On 10/17/2010 5:05 PM, mark drillock wrote:
>>> The 80-84 used 3 pin brake pressure switches
>>> The 85-91 used 2 pin pressure switches
>>>
>>> Mark
>>>
>>>
>>>
>>> John Rodgers wrote:
>>>> '91 Carat, auto tranny (maybe they all have them) - brake lights won't
>>>> go of - stuck "On". pulled the fuse to protect the circuit.
>>>>
>>>> Question: Does the Carat - particularly the '91 Carat - use a pair of
>>>> three connector brake light switches - or 2 connector brake light
>>>> switches.
>>>>
>>>>
>>>
>>
>>
>
>