Specifications

- Additional Coolant Temperature Switch:
A second switch has been added to the system and it is located in a
new thermostat housing on the 3.0L models and in the intake manifold
coolant passage on V6 and Small Block V8 models.
This switch is used to keep the TKS unit from opening (when the
engine is warm), which prevents additional fuel from entering the
engine under hot re-start conditions.
One lead is wired to the circuit breaker (i.e. battery power via an in-line
fuse) and the other lead is wired to the TKS unit. This switch is
normally open and closes (completing the circuit) above 130 degrees
F.
When the engine coolant temperature reaches 130 degrees F, the
coolant temperature switch closes and remains closed until the coolant
(or sea water on sea/raw water cooled engines) temperature drops
below 110 degrees F. When closed, the switch sends 12Vdc to the
TKS Module, thus keeping the additional fuel flow path closed until the
engine cools sufficiently to warrant the additional starting fuel.
Once the coolant temperature drops below 110 deg F. the coolant
temperature switch opens and the 12Vdc is no longer sent to the TKS
module. The TKS unit will cool allowing the needle to back off the seat
and aid in the next starting event.
The wiring harness will be equipped with a diode to prevent power
from this source running back on the purple lead, which would keep
the engine running after a commanded stop.
Coolant Temperature Switch