TM 9-2330-271-14&P
Table 4-2. Troubleshooting - Continued
Table 4-2. Troubleshooting - Continued
MALFUNCTION
MALFUNCTION
TEST OR INSPECTION
TEST OR INSPECTION
CORRECTIVE ACTION
CORRECTIVE ACTION
ELECTRICAL SYSTEM - Continued
BRAKE SYSTEM - Continued
Step 4
Check for dirty or corroded lamp sockets,
Step 6.
Check to see if air reservoir drain cock is open
cable connectors or harness contacts.
Close air reservoir drain cock
Clean as necessary.
Step 7.
Inspect brake shoe retraction spring to determine
4.
DIRECTIONAL SIGNALS INOPERATIVE.
if spring is weak or broken
Step 1.
Check for defective flasher or switch in towing
vehicle
2.
NO BRAKES OR WEAK BRAKES
Replace defective part
Step 1.
Check to see if shutoff valves on towing vehicle
Step 2.
Check light assembly
are closed
Open towing vehicle shutoff valves
Step 2.
Inspect intervehicular air hose for proper
Step 3.
Inspect for dirty or corroded lamp sockets or
connection
contacts
Connect air hose properly
Remove lamp and clean socket and contacts.
Step 3.
Check to see If semitrailer air reservoir drain
5.
ALL 110-VOLT LAMPS FAIL TO OPERATE
cock is open
Step 1
Check power cable connection
Close air reservoir drain cock
Pull plug out and insert fully.
Step 4.
Check to see If air pressure is low
Step 2
Check to see if current Is available from power
Check air pressure gage on towing vehicle
source.
Remove any restrictions in air lines Make
Check power source for failure.
6.
ONE OR MORE 110-VOLT LIGHTS WILL NOT
connected and brakes applied, coat couplings,
LIGHT
connectors and fitting with soap and water
Step 1
Check to see if lamp is defective.
solution No leakage is permissible
Step 5.
Check relay valve for defect
3-16)
Step 2
Inspect for dirty or corroded lamp socket or
Replace if necessary.
contacts.
Step 6.
On those semitrailers incorporating an air
Remove lamp and clean contacts.
filter, inspect for clogged filter
Step 3
Inspect for broken wire or loose connections
Tighten, repair, or replace wire
Step 7.
Check for air in hydraulic brake system
Step 4
Check for defective light assembly
Step 8.
Check for leaks in hydraulic system
Tighten connections
7.
ONE OR MORE FLUORESCENT LAMPS WILL NOT LIGHT
Step 9.
Inspect for grease or brake fluid on brake
Step 1
Check to see if lamp is defective.
lining.
Step 2.
Check to see if ballast is defective
and replace wheel cylinder, if necessary
Step 3.
Check to see if fixture is defective
Step 10.
Check to see if brakes are out of adjustment
BRAKE SYSTEM
Step 11.
Check for worn brake linings
1.
BRAKES WILL NOT RELEASE.
Replace brake shoe if lining is worn (para-
Step 1.
Check to see if relay valve Is in applied
graph 4-35)
position.
Step 12.
Check to see if brake fluid is low in master
Build up pressure in semitrailer brake system
cylinder.
If trailer is coupled. Open drain cock in semi-
Fill master cylinder with brake fluid or re-
trailer air reservoir If van is uncoupled.
Step 2.
Inspect intervehicular air hose for proper
connection
Step 13.
Check for defective master cylinder
Connect hose properly.
Step 3.
Check to see if brake on towing vehicle is in
applied position.
Step 14.
Check for defective wheel cylinder
Release towing vehicle brake
Step 4.
Check for restrictions in service and emergency
air lines, or intervehicular hose.
3.
SLOW BRAKE APPLICATION OR SLOW RELEASE.
Straighten Kinks and bends in lines or hose
Step 1.
Check to see if air pressure is low
Step 5
Check to see if shutoff valves on towing vehicle
Check air supply Make leakage test (para-
are in closed position
graph 4-44)
Open towing vehicle shutoff valves.
4-11