TM 9-2320-209-34-2-3 (4) Cycling test. FRAME 1 1. Be sure control switch (1) is in OFF position. Flip HI-LO switch (2) to HI position. Start heater (3) and let it run until it transfers to LO heat all by itself. 2. Wait a few minutes after heater (3) transfers to LO heat. Measure tempera- ture of coolant at outlet hose (4) by letting coolant run on thermometer. WARNING Coolant will be hot. Use caution when working near hot coolant. Severe burns could result. 3. Temperature should be between 170°F and 195°F. 4. Flip control switch (1) to OFF position. Let blower motor stop. 5. If temperature is not as specified, get new restriction thermostat. Refer to para 21-6c and para 21-6e. END OF TASK 21-12