[T3] Brake Lights...

[Jim Adney]

On 28 Feb 2018 at 21:10, J. Jonik wrote:

> Recently replaced Master Brake Cylinder ('71 T 3).   Brakes work
> fine....but belatedly, noticed that the brake lights don't work.   Is
> the likely cause that the electric plug in the Master Cylinder is
> faulty?...or that it's not in the proper hole in the cylinder?   Are
> both of those electric plug things the same? 

The 2 switches on the MC are identical and wired in parallel, so they are 
redundant. If you've got no brake lights, assuming the wiring and bulbs are 
okay, it means that BOTH switches have gone bad. This is common, 
because when one goes bad things still work normally. It's only when the 
2nd one goes bad that the lights fail.

On your '71, the 2 switches should both be pointing to the L (US driver's) 
side. That's true for all years except for single circuit cars and '70s with the 
OE style MC.

Switching switches or wires around doesn't buy you anything, and I don't 
think there's any way to put the switches in holes that prevent them from 
working.

> The emergency light push-button on the dashboard passes the push/light
> test.  What if I switch electric plugs on the master cylinder to see
> if the emergency button doesn't light...thus showing that an elec.
> plug is shot?   I don't want to just switch the wires: they "remember"
> where they were when removed....one reaching further than the other. 

The 68-71 dash pushbutton only checks the dash bulb.

Unless there's a problem with your wiring or bulbs, you have 2 bad switches.

I stock switches, but they should be rather easy to find locally. When you 
replace switches, you won't have to rebleed. Just have everything ready so 
you can do it quickly. And don't overtighten the new switch; there's nothing 
quite like breaking off that little pipe thread just because there's a great big 
hex available.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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