re: '74 GTV brake light

[Dana Loomis <dloomis@domain.elided>]

> oday the brake light in my instrument cluster suddenly came on.  I first 
>pulled the wire off the switch at the hand brake, the light stayed on.  Then 
>i got under the hood and pulled all 4 plugs on the brake reservoir off and  
>the light STILL stayed on.  The brakes work well and the reservoir is full.
>  From the schematic, it seems that the culprit might be  device #13,   the 
>"service brake pressure warning light switch" or a wire shorted to ground.  I 
>don't know where the brake pressure warning switch is, all the wires from the 
>reservoir go right  into the firewall... can anyone help me here?

First of all, the way these things are wired, pulling the wires off the
brake fluid reservoir will make the warning light stay on.  You'll need to
hook everything up again to troubleshoot it.  The "service brake pressure
warning light switch" is on the passenger side firewall, down low where the
fuel and brake lines exit the engine compartment toward the rear of the
car.  Look for a junction with several brake lines coming together and a
wire on top.  As I recall, everything in this system is grounded directly
to the chassis, without any ground wires.  You may have a brake problem, a
loose wire, or a bad switch.  If the brakes are OK, check to see that the
wire is connected to the junction on the firewall and that the floats
inside the reservoir are moving freely.

Dana Loomis
2000 GT Veloce
1750 GT Veloce

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