Wrangler L6-258 4.2L VIN C 2-bbl (1988)
Thermal Electric Switch: Description and Operation
Thermal Electric Switch
There are two of these switches located in the air cleaner housing and their purpose is to indicate to the MCU a cold-start or hot-start condition. The
switches are activated by the temperature of the air entering into the air cleaner.
If the air entering the air cleaner is below 10~C (50~F), the switches are normally closed. If the switches are closed, then the MCU receives voltage
signals. The voltage signals indicate to the MCU a cold-start condition. The MCU compensates for a cold-start condition by richening the air/fuel
mixture and advancing the timing.
Above 18~C (65~F), the switches are normally open. If the switches are open, the MCU gets no voltage signal. Lack of a voltage signal indicates to the
MCU a warm engine start-up condition.
