DeTomaso Mailing List: November 99, Message #365

John,   I read with interest your posts and commend you on your diligence to 
troubleshoot the problem.    You said that you had no power indicated to the 
Stop Lamp Switch.... Therein lies the problem, and it's easy to trace.  

I view the Brake Light circuit as a dedicated circuit not dependent upon the 
Starter Interlock or the Override.  The Brake Light circuit is supplied power 
from fuse #12, which in turn is supplied power from the "ON" position of the 
Ignition switch, which in turn is supplied by the battery (also being the 
charging circuit) via the ammeter.  Fuse #12 also supplies power to the Turn 
Indicator Switch, the Courtesy Lights, the Radiator Fan relays, the Seat Belt 
and Brake Warning lamps and the Tachometer.  So if these are operable, I 
would conclude that the "ON" circuit of the Ignition switch is good.

I don't see the Washer, Wiper or Brake circuits utilizing the Starter 
Interlock Override.... Quite the opposite.... The power lead to the Stop Lamp 
Switch also enables the Override.  It, in conjunction with the ground 
borrowed from the Washer Motor, activate the Override coil which in turn 
completes the cranking circuit that the Starter Interlock can sever.  I don't 
look to the Interlock or the Override for causes of the Brake Light failure.
You inferred that the cranking circuit works, so the Starter Interlock has 
not severed the Cranking circuit.

I view the Washer Motor circuit as being a dedicated circuit totally removed 
from the Starter Interlock and Override.  On the diagram, the Wiper and 
Washer green wire circuit is supplied power from the heavy gauge violet wire 
that originates at fuse #8. (on my car the green wire circuit is supplied 
directly from fuse #9).  Tracing up the power supply trail, fuses #7, 8 and 9 
are supplied from the battery (also being the charging circuit) via the 
ammeter.  So if the Wiper circuit is, and the Washer Motor circuit is not 
operative that would lead me to suspect the that the major grounding terminal 
up under the dash may not be secure.

I suggest that you secure all wire terminators on the suspected circuits and 
tighten up the major grounding terminal as well as the connections to the 
battery and the ammeter.

I assume the Starter Interlock is a safeguard to insure that driver and 
passenger have their seat belts fastened.

Good Luck,
Brent, ..... considering swapping in a VW wiring harness.

<< Still no go on the brake lights.  I changed all the plastic fuses today to
 the Busse fusses that Jack champions.  This really comes as no surprise as
 the wiring diagram (which I may be misreading) does not show its voltage
 coming through the fuse box. Additionally, my windshield washer( not wiper)
 motor is not functioning.
 
 According to the wiring diagram both utilize the Emergency Starter Interlock
 Override which may be the culprit.  My car is an early '73 with relays on
 drivers left.  Is anyone familiar with this Override and where I might find
 it on my car? >>