compustar timer add on to temp sensor con

I would like to hook a 556t programable timer to a compustar stater.The model # 1wam-s with a cm4200 contoller and has a temp sensor port which in default mode can be used to start the starter.Connector 5 has a 3 pin connector (-) black pin 3 (temp) Brown pin 2 (+) gray pin 1 The wire from the 556t is a neg pulse,which pin would I use ? thanks

CONNECTOR 5 (Optional Temperature sensor) PIN 1 Gray-12-volt (+) positive output. This wire will provide 12-volt (+) positive to temperature sensor. PIN 2 Brown-Temp sensor (-) negative input. This wire will activate remote start when provided a (-) negative input. (Note: If vehicle is remotely started, a (-) negative input will turn the vehicle off.) PIN 3 Black-Temp sensor (-) negative ground output.