TM9-2330-371-14&P
ORGANIZATIONAL TROUBLESHOOTING
The following provides procedures that the organizational mechanic can use to locate and correct
M270A1 semitrailer malfunctions. Semitrailer must be hooked up with tractor when performing
electrical or airbrake system tests.
ORGANIZATIONAL TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
ELECTRICAL SYSTEM
1. ALL LAMPS DO NOT WORK.
Check for open circuit in wiring.
Step 1.
a. With towing vehicle lights turned on, check tractor-to-trailer connector by
measuring voltage between ground contact and other contacts.
If measurement is not approximately 24 vdc, perform towing vehicle
troubleshooting.
b. Check lead assembly (receptacle) by measuring continuity between ground
contact and other bare metal on semitrailer.
If measurement is not zero, remove, clean, and install ground wire 90
If measurement is still not zero, replace lead assembly (receptacle)
c. With semitrailer lights turned on, disconnect wiring harness connector and
measure voltage between wiring harness connector and other bare metal on
semitrailer.
If measurement is not approximately 24 volts, replace wire harness
Step 2.
Check all connectors, lamp sockets, and lamps for corrosion and damage.
If connectors, sockets, or lamps are corroded, scrape and clean off
corrosion (page 4-25).
If connectors, sockets, or lamps are damaged, replace them
