TM 9-4120-388-14
4-40. MODE SELECTOR (ROTARY) SWITCH (S1) - Continued.
Test.
c.
(1) Using multimeter and switch position chart shown in Figure 4-43, check continuity at contacts indicated.
With switch position dosed, continuity should be indicated. With switch position open, no continuity should
be indicated. Check between each set of contacts and at each switch position.
SELECTOR
SWITCH WAFERS AND TERMINALS CONNECTED "
FUNCTION
SWITCH
S1A
S1B
S1C
S1D
POSITON
1
HEAT
12 AND 1A
21 AND 2C
42 AND 4A
32 AND 3A
(HIGH)
41 AND 4C
HEAT
12 AND 1A
21 AND 2C
2
(Low)
3
OFF
VENT
21 AND 2C
4
12 AND 1B
21 AND 2C
5
11 AND 1D
NOT USED
TEST POINTS
(2) Replace switch if it fails above test.
d. Replace. (Assuming switch has been pulled from box for above test)
(1) Tag and disconnnect leads.
(2) Remove witch.
Installation.
e.
(1)
Reattach leads in place using tags and wiring diagram. (See Figure 4-16.)
(2)
Slip switch into control box and place shaft through hole.
(3)
Holding backside of switch, secure switch to box with Iockwasher and nut. Be sure that switch positions
match front plate.
(4)
Insert rear panel into box and align holes.
Secure rear panel with four screws and lock nuts.
(5)
Place knobs on switch shafts and align setscrews with flats on shafts.
(6)
Tighten setscrews in both knobs.
(7)
(8)
Install control panel. (See para 4-37.)
