OK, thanks for that. As I have time to troubleshoot, I find I am getting
red-yellow hot all the time as is normal. Blue-gray connects the two
switches as a fail safe and runs off to the brake warning light just in
case both fail, I suppose.

That means that red-black is the problem, I think. Red black goes to a four
pin connector that comes out of the dash, obviously going back to the
lights. Since the lights work when I jumper the two reds, giving power to
red-black from red-yellow, I suppose the problem is between the switches
and the 4-pin connector. I will try to check that out now.

Jim

On Fri, Oct 9, 2015 at 1:26 PM Neil N <musomuso@gmail.com> wrote:

> You have an '82 diesel? Looking at that in Bentley.....
> S8 supplies constant (battery) + to brake switches via a red/yellow wire.
> This wire enters one switch connector then splits off to the other.
> You should see constant 12 volts at each yellow/red wire.
> In a similar manner, a red/black wire goes from one switch connector to
> the other,
> becoming 1 red/black wire which carries + to brake lights when either
> switch closes.
> You should see 12 volts at either wire when brake pedal pushed down.
>
> Suggestions:
> (likely NOT the cause) test brake lights with brake warning light
> disconnected.
> Test brake lights with one switch plugged in at a time.
> Test brake lights while moving wires to switches.
>
> Ground is constant.
> FWIW brake light ground is at "in connection box"
> ..... whatever that means.  ;)
>
> Neil.
>
> On Fri, Oct 9, 2015 at 10:23 AM, Jim Felder <jim.felder@gmail.com> wrote:
>
>> Another thing, if anyone is so inclined to do so, I need to understand how
>> the switches are supposed to work. It looks to me like there is always
>> power to the switch, and the pressure interrupts the ground, which is the
>> bottom of the U-shaped arrangement of terminals, the two opposing
>> terminals
>> being red and red yellow wires, so maybe it is the ground wire I need to
>> chase down?
>>
>>
>>
>> On Fri, Oct 9, 2015 at 11:43 AM Jim Felder <jim.felder@gmail.com> wrote:
>>
>> > Bought two new switches this morning and installed them. No brake
>> lights.
>> > When the connectors are jumpered (the two opposing positions) both brake
>> > lights come on. Getting power to them obviously. What else could be
>> wrong?
>> > Still out there with a voltmeter and a bentley, trying to make sense of
>> > both. If the brake light switch connectors are getting power, and the
>> > lights come on when the power is jumpered, and the old parts were new,
>> and
>> > the new parts are newer, then what else could there be that keeps these
>> > lights from actuating? I just don't get it.
>> >
>> > Jim
>> >
>> > On Fri, Oct 9, 2015 at 10:36 AM John Rodgers <jrodgers113@gmail.com>
>> > wrote:
>> >
>> >> My experience with the lights when not working has been to take each
>> >> fixture apart and clean the heck out of the connections getting rid of
>> any
>> >> rust and corrosion. Made sure there was good metal to metal contact
>> where
>> >> needed. Cleaned all lenses and lubed the seals with a little silicon
>> >> lubricant, then reassembled them.
>> >>
>> >> Never dealt with a switch failure. That's a whole 'nother horse!
>> >>
>> >> John
>> >> On Oct 8, 2015 20:43, "Stuart MacMillan" <stuartmacm@gmail.com> wrote:
>> >>
>> >> > I’ve had way too many of these fail.  And, for some reason, they
>> seem to
>> >> > fail at the same time.  Supposedly, if only one fails the brake
>> warning
>> >> > light should go on when you apply the brakes, but that has never
>> >> happened.
>> >> > Aftermarket suppliers can’t seem to make switches that can take high
>> >> > pressure for very long. If the dealer still sells them get them
>> there,
>> >> they
>> >> > are just too important to take chances.
>> >> >
>> >> >
>> >> >
>> >> > Stuart
>> >> >
>> >> >
>> >> >
>> >> > From: Jim Felder [mailto:jim.felder@gmail.com]
>> >> > Sent: Thursday, October 08, 2015 3:13 PM
>> >> > To: Stuart MacMillan; vanagon@gerry.vanagon.com
>> >> > Subject: Re: Help me diagnose and fix no brake lights
>> >> >
>> >> >
>> >> >
>> >> > I have the three-pin connectors, but shorting the facing two causes
>> the
>> >> > brake lights to work. This isn't among the last work done, it was
>> done
>> >> two
>> >> > years ago when I did the brakes and suspension. That's not a very
>> long
>> >> life
>> >> > for a brake switch, in my opinion. I wish I could remember when I got
>> >> them
>> >> > from so I wouldn't make the same mistake twice.
>> >> >
>> >> >
>> >> >
>> >> > Thanks, all. I'll let you know if the new new switches work, but I'm
>> >> > pretty sure that's going to be it.
>> >> >
>> >> >
>> >> >
>> >> > Jim
>> >> >
>> >> >
>> >> >
>> >> > On Thu, Oct 8, 2015 at 3:54 PM Stuart MacMillan <
>> stuartmacm@gmail.com>
>> >> > wrote:
>> >> >
>> >> > First, short the two wires on each switch together and see if the
>> lights
>> >> > go on.  If not, it's likely wiring, if they do, it's the switches.
>> >> Replace
>> >> > both of them. It's not uncommon for these to fail.
>> >> >
>> >> > Stuart
>> >> >
>> >> > -----Original Message-----
>> >> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> Behalf
>> >> > Of Jim Felder
>> >> > Sent: Thursday, October 08, 2015 12:27 PM
>> >> > To: vanagon@GERRY.VANAGON.COM
>> >> > Subject: Help me diagnose and fix no brake lights
>> >> >
>> >> > Daughter was driving behind me in the Westy today and called me to
>> say
>> >> > neither brake light was coming on. All other lights working. Brakes
>> >> > excellent, newish MC and brake light switches.
>> >> >
>> >> > All fuses look good. Where should I start looking?
>> >> >
>> >> > Thanks in advance for your help. I need to head out of town overnight
>> >> next
>> >> > friday.
>> >> >
>> >> > Best,
>> >> >
>> >> > Jim
>> >> >
>> >>
>> >
>>
>
>
>
> --
> Neil n
>
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>
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>
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