Re: 1969 Dual-Circuit Brake Light Sender

[Caxambu@domain.elided]

Hi,

There are three pressure senders on the hydraulic tee fitting mounted on the 
firewall in front of the driver. The two larger front-facing senders on 
either side are the brake light switches. They are redundant-- the brake 
lights will work with only one switch functional. The smaller center 
upward-facing switch is for that red pressbutton gizmo on the dash. (What 
exactly is it for???) There are no switches in the pedal box. First check the 
fuse, it's the one second from the left. The same fuse serves the windshield 
wiper motor so if the wipers don't work you've probobaly found the problem.

In my experience the pressure switches and nearby wiring are what fail, being 
close to the exhaust manifold and subject to heat and old brake fluid. Test 
the rest of the circuit by jumpering the two wires that plug into one of the 
above-mentioned brake switches-- the brake lights should glow. If they glow 
when jumpered but not when plugged into the switch and pressing on brakes 
then the switch is bad. These are available from the usual suppliers, 
although in a pinch I have sucessfully used readily available locally 
brakelight switches from mid-60's - 70's VWs. At about 1/2 - 1/4 the price.

I get nervous driving a roundtail w/o brake lights. During the day, on my way 
to the local "Bug" store to buy the above-mentioned emergency replacement 
switch I turned on my parking lights each time I used my brakes and kept a 
wary eye on the rearview mirror.

- --Caxambu
1969 Spider 1750
Seattle WA, not too much spider weather this week.


>  Date: Thu, 24 Jun 1999 11:24:40 -0700
>  From: "W.B. Peale" <peale@domain.elided>
>  Subject: (Don't Want No) SUV In Da Butt
>  
>  Howdy.  My brake lights have stopped working and I'm caught without access
>  to any Alfa manuals as we've just moved and everything is still in boxes.
>  Any help would be much appreciated.
>  
>  This is a '69 car with the "sophisticated" dual-circuit system.  Bulbs and
>  contacts in the rear are fine and all fuses appear to be good.  My guess is
>  that the lights are triggered by one of three(!) senders on the a little
>  front/rear 'proportioning valve' unit on the firewall, but there could be a
>  switch inside the pedal box. (Only two of the three senders are wired at
>  this point.)
>  
>  Any advice on testing/wiring the senders and/or getting the brake lights
>  back on line?  This is my daily driver and I'd like to protect its little
>  rear end from SUV sodomization!
>  
>  W. B. Peale
>  69 GT Veloce
>  
>  ------------------------------

------------------------------