when the shutters are fully open.
Replacement. Remove the actuators in accordance with paragraph 15-26h and replace them in accordance with
15-29. LIMIT SWITCHES. There are four limit switches (15, figure 15-16) used in conjunction with the four louver
Connect ohmmeter (Rx1 scale) to terminals of switch.
Toggle switch several times to closed position; ohmmeter should read zero to 1 ohm in the closed position
and read infinite ohms in the open position.
Replacement. Remove the limit switches in accordance with paragraph 15-26h and replace them in accordance
with paragraph 15-25a.
15-30. RELAY ASSEMBLY. The actuator control relay assembly used in conjunction with the housing kit is located in
the external power box and consists of four relays K60, K61, K62, and K63; terminal board TB303; four fuses F60, F61,
F62, F63; and a mounting bracket.
Test. Refer to figure 15-24 and proceed as follows:
Apply 24V DC across relay coil K60, monitor contacts of relay with ohmmeter. Check that normally open
contacts (3, 6, and 1, 4) are now closed and check that normally closed contact (3, 5, and 2, 4) are now
Remove 24V DC and check that normally open contacts (3, 6, and 1, 4) are now open, and check that
normally closed contacts (3, 5, and 2, 4) are now closed.
Repeat steps (1) and (2) for relay coils K61, K62, and K63.
15-31. RADIATOR SHUTTERS AND ACTUATORS. Two shutter actuators (see figure 15-22) are used in conjunction
with the housing kit. Radiator coolant is circulated to the actuators which expands parafin contained inside the actuator
housing. The parafin expands as coolant temperature increases and, in turn, drives the actuator piston which is
connected to the shutter assembly.
Inspect. Inspect the radiator shutters for bent or broken vanes. Inspect the radiator coolant lines to the actuators
for leaks and loose connections.
Adjustment. Refer to figure 15-22 and proceed as follows:
The following adjustment must be made when the radiator coolant is cold.
Remove cotter pins (9) and adjust rod (10) so that radiator shutters are fully closed. Ensure that actuator
piston is fully retracted.
Reinstall cotter pins (9).
Replacement. Remove the radiator shutter actuators in accordance with paragraph 15-26b. and replace them in
accordance with paragraph 15-25f.