KNOWN INFO
Is vehicle equipped with a
100 AMP reverse polarity
relay?
TEST OPTIONS
11.
Circuit breaker CB70 OK.
Battery(ies) OK.
Cab to chassis ground strap
OK.
PDP to cab ground cable OK.
Shunt OK.
Starter to shunt 24 VDC cable
OK.
Battery to shunt cable
assembly OK.
Starter to chassis ground
cable OK.
POSSIBLE PROBLEMS
Faulty 100 AMP reverse
polarity relay.
Faulty battery to 100 AMP
reverse polarity relay 12 VDC
cable.
Faulty 100 AMP reverse
polarity relay to PDP 12 VDC
cable.
Faulty 200 AMP reverse
polarity relay.
Faulty 200 AMP terminal
block.
Faulty 200 AMP terminal block
to PDP 12 VDC cable.
Faulty 200 AMP terminal block
to reverse polarity relay 12
VDC load cable.
Faulty 200 AMP terminal block
to reverse polarity relay 12
VDC battery cable.
Faulty battery to 200 AMP
terminal block 12 VDC cable
assembly.
REASON FOR QUESTION
Visual Inspection
YES
Go to step 14 of this fault.
This question eliminates
possible problems and
determines where
troubleshooting continues.
NO
TM 9-2320-365-20-1
2-256.18 Change 1
e3. 12 VDC AND 24 VDC CIRCUITS DO NOT OPERATE (CONT)
