TM 9-2330-294-14
CPR 102836 for semitrailer No. 1 through 200 and
b. Wiring Harness Short Circuit Test.
11675789 for semitrailer No. 201 and on.
(1) Inspect harness CPR 102836 and 102845 for
(5) If no circuit is found in performing (4)
semitrailer no. 1 through 200 and harness 11675789
above, remove all bulbs from the trailer lights and
and 11675775 for semitrailer no. 201 and on for
any apparatus connected to the utility outlet.
(6) Repeat (4) (a ) through (d ) above.
(2) Remove bulbs from the light assemblies
which are not operating.
(7) Perform a continuity short circuit test of all
pins on the trailer receptacle (J1) in the following
manner:
locate pins of the suspected defective circuit in the
(a ) Connect the positive meter lead to pin A.
Connect the other meter lead to the other pins of the
receptacle (B, C, D . . . N consecutively) one at a
following short circuit test:
(a ) Place the range selector on the meter in
time.
(b ) Remove the positive meter lead from pin
the Rx1 position.
A and connect to pin B. Connect the other meter lead
(b ) Assure meter is set for "DC" operation.
to the other pins of the receptacle (C, D, E . . . N
(c ) Assure one end of both meter leads are
consecutively) one at a time.
plugged into the proper jacks on the meter.
(c ) Repeat (b ) above until all remaining pins
(d ) Short the free ends of the two meter leads
together and adjust the meter for zero ohms.
(C through N) have been connected to the positive
meter lead and tested against all the other pins of the
(e ) Unshort the meter leads. Connect one
lead to ground and the other lead to the trailer
connector.
receptacle pin of the suspected defective circuit.
(d) In performing tests (a) through (c)
above, no deflection of the meter should occur except
(f ) In performing step (e), no deflection of
the meter should occur. However, if pin "N" is being
for the following:
tested, the following reading should be obtained: Pin
N to ground full scale deflection with air pressure
(2) Pin N to D or Lcontinuity with air
pressure below 65 psi.
below 65 psi.
(g ) Any pin being tested which results in a
4-16. Circuit Breaker Replacement
full scale meter deflection (other than pin "N" of (f )
above) indicates a short to ground. Repair main
a. Removal.
harness branch end wires as required. Notify direct
(1) Remove boot (jam nut within) and lock
support personnel for repair of wires buried in main
washer securing circuit breaker to mounting bracket.
body of harness.
(2) Pull circuit breaker to rear until clear of
(h ) It should be noted that if the service
bracket.
clearance lamp circuits are being tested and a short
(3) Remove two screws and lock washers
condition exists, then an additional short circuit test
securing electrical leads to circuit breaker and
must also be made on each CPR 102845 harness for
remove circuit breaker.
semitrailer No. 1 through 200 and 11675775 harness
b. Installation. Discard jam nut and keyway
for semitrailer No. 201 and on, connected between
washer from new circuit breaker. Install circuit
each clearance lamp assembly and the main harness
breaker in reverse order of removal (a above).