TM 5-3895-370-14&P
Table 4-4. Unit Troubleshooting Procedures - CONT.
Malfunction
Test or inspection
Corrective action
ELECTRICAL SYSTEM (CONT)
Step 2. Check voltage on 12-volt socket/cable (terminal R) at top of terminal strip (red wire) in
junction box.
If 12 +3 vdc are not measured, replace 12-volt socket/cable (para 4-91).
If 12 +3 vdc are measured, go to step 6.
Step 3. Check continuity across 24-volt cable (connector, terminal B and yellow wire in resistor box).
If there is no continuity, replace 24-volt cable.
If there is continuity, go to step 4.
Step 4. Check resistance across stoplight resistor.
If resistance is not 5 +2 ohms, replace resistor box (para 4-74).
If resistance is 5 +2 ohms, go to step 5.
Step 5. Check voltage on resistor/junction cable at terminal strip (stoplight terminal) in junction box.
If 12 ±3 vdc is not measured, repair or replace resistor/junction cable
(para 4-74 and 4-75).
If 12 ±3 vdc is measured, go to step 6.
Step 6. Check voltage on junction/breaker cable (red wire) on left side of circuit breaker box.
If 12 +3 vdc is not measured, repair or replace junction/breaker cable
(para 4-75 and 4-76).
If 12 +3 vdc is measured, go to step 7.
Step 7. Check voltage on opposite side of stoplight amp breaker.
If 12 +3 vdc is not measured, replace amp breaker (para 4-76).
If 12 ±3 vdc is measured, repair or replace chassis wire harness (para 4-88).
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