The upper switch is called the Thermo Time switch. It engages the injector solenoid on the intake manifold via the relay on the left fender well by the safty latch, when the starter is engaged. the colder the engine temp the longer the duration of the injection.
The lower temperature switch is for cold start ignition timing advance, When the engine is Below 17deg C. this switch connects to ground and signals the timing controll relays, the two black boxes on the left of the motor by the battery, to release the vaccuim retard, thus advancing the timing for improved fast idle speed when the motor is first started.
Al Lieffring
66 230SL
