TM 9-2320-260-20
Table 2-4. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
30. COOLANT TEMPERATURE GAGE INOPERATIVE
NOTE
If STE/ICE is available, perform NG31 - gage test (chapter 2,
section VII).
Test 1. Test coolant temperature gage operation.
Step 1. Disconnect lead 33 from coolant temperature sending unit.
Step 2. Turn battery switch to ON position.
Step 3. Turn ignition switch to RUN position.
Step 4. Coolant temperature gage should read minimum temperature.
Step 5. Touch contact end of lead 33 to frame ground. Coolant temperature gage should read
maximum temperature.
a. If coolant temperature gage operates properly, go to test 3 and check sending unit.
b. If coolant temperature gage does not operate properly, go to test 2.
Test 2. Test for battery voltage into temperature gage, go to malfunction 29, test 2.
Test 3. Test temperature sending unit.
Step 1. Start vehicle engine (TM 9-2320-260-10).
Step 2. Set multimeter to RX1 scale.
Step 3. Touch negative lead of multimeter to engine ground.
Step 4. Touch positive lead of multimeter to sending unit. Multimeter reading should decrease
as engine coolant temperature increases.
a. Replace temperature sending unit if resistance does not show any decrease as
temperature increases (para. 4-28).
b. If resistance does show a decrease as temperature increases, go to test 4.
Test 4. Check continuity of lead 33.
Step 1. Disconnect lead 33 from temperature gage.
Step 2. Set multimeter to RX1 scale.
Step 3. Touch negative lead of multimeter to contact end of lead 33 at sending unit.
Step 4. Touch positive lead of multimeter to other end of lead 33.
a. Repair or replace lead 33 if continuity is not present (para. 4-52).
b. Replace temperature gage if continuity is present (para. 4-10).
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