Thermo King Super II SR+, Manual, Page: 58 / 145

Electrical Maintenance (Rev 6/98)
48
indicates a completed circuit with the gauge reading
35.6 mm (1.4 in.) H
2
0. Release the pressure.
Repeat the procedure several times to be sure the set-
ting is correct.
Remove the test equipment. Connect the wire and air
sensing tubes to the switch. The BLACK hose from the
high pressure or air inlet side of the evaporator coil
connects to the hose fitting on the side of the air switch
stamped BLACK. The CLEAR hose from the low pres-
sure or air outlet side of the evaporator coil connects to
the hose fitting on the side of the air switch stamped
CLEAR.
NOTE: Route hoses for continuous slope to avoid
condensate traps.
If too much frost continues to accumulate before defrosting,
decrease the pressure setting. Turn the adjustment screw
counterclockwise.
If defrost action occurs with too little frost accumulation,
increase the pressure setting. Turn the adjustment screw
clockwise.
OIL LEVEL SWITCH
The oil level switch is located in the oil pan on the back side
of the engine. The switch is open when the oil level is above
the actuation point. The switch is closed when the oil level
is below the actuation point.
To test the switch on the unit:
1. Make sure that the unit is turned off.
2. Connect a continuity tester to the OLS circuit (pin J2)
and the 8F circuit (pin M3) at the relay board.
3. Check the oil level with the dipstick and make sure that
it is between the low mark and the full mark. Add oil if
necessary.
4. The switch should open and there should be no continu-
ity between the OLS and the 8F circuits with the oil
level between the low mark and the full mark on the
dipstick.
Bench test the oil level switch if there is continuity
between the OLS and the 8F circuits and there are no
short circuits in the OLS and the 8F wires.
5. Drain the oil from the engine and observe the continu-
ity tester. The switch should close and the continuity
tester should indicate a complete circuit when the oil
level falls below the actuation level of the switch.
Bench test the oil level switch if there is no continuity
between the OLS and the 8F circuits and there are no
open circuits in the OLS and the 8F wires.
Switch Removal and Installation
1. Disconnect the switch wires from the main wire har-
ness before removing the switch.
2. Remove the push-in style switch by carefully prying
the switch out of the oil pan.
3. Install the push-in switch by carefully pushing the
switch into the oil pan.
4. Connect the switch wires to the main wire harness after
installing the switch.
Bench Test
1. Disconnect the oil level switch wires from the main
wire harness and remove the switch from the oil pan.
2. Use a small container partially filled with engine oil to
check the float and make sure that it floats in engine oil
and that it slides freely between the upper and lower
stops.