TM9-2330-207-14
Table 4-3. Organizational Troubleshooting Table
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
ELECTRICAL SYSTEM (See schematics as follows:)
Fig. No.
2-22 Electrical wiring diagram (M127 and M127A1)
2-25 Chassis wiring diagram (M127A1C, M128A1, M128A1C, M129A1, M129A1C)
2-27
Chassis wiring diagram (M127A2C, M128A2C, M129A2C)
12-volt body wiring diagram (M128 and M129 Series)
2-28
2-29 24-volt body wiring diagram (M128 and M129 Series)
2-30
110-volt ac body wiring diagram (M129 Series)
1. 12- OR 24-VOLT LAMPS DO NOT LIGHT.
Step 1. Check intervehicular cable receptacles for proper connections.
Pull plug out and reinsert fully.
If receptacles not defective, proceed to step 2.
Step 2. Check setting of light switch on towing vehicle.
Set light switch properly.
If light switch is set properly, proceed to step 3.
Step 3. Check circuit breaker and wiring on towing vehicle.
If circuit breaker open, reset circuit breaker.
If circuit breaker not open, proceed to step 4.
Step 4. Check wiring for bare spots in insulation.
Repair wiring if defective. Refer to para. 4-26.
If wiring not defective, proceed to step 5.
Step 5. Check ground connector for loose or broken connections.
Repair or tighten ground connector (para 4-26c).
2. ONE OR MORE LAMPS ON CHASSIS OR BODY WILL NOT LIGHT.
Step 1. Check for burned out lamp.
Replace lamp if defective (para. 4-19, 4-20, 4-21).
If lamp does not light, proceed to step 2.
Step 2. Check for broken or shorted wire in cable or loose connection in plug or receptacle.
Tighten, repair or replace as necessary (para. 4-26).
If wiring and connections not damaged, proceed to step 3.
Step 3. Check for damaged light assembly.
Replace light assembly, if damaged (figs. 4-11 thru 4-20).
If light assembly not damaged, proceed to step 4.