TM 1-1740-221-13&P&P
FIELD MAINTENANCE
POWER DISTRIBUTION BLOCK (FUSE/RELAY HOLDER)
INITIAL SETUP:
Test Equipment
References
Multimeter (WP 0157, Item 14)
Equipment Condition
Tools and Special Tools
Engine Shut Down
Fuse Puller Tool (WP 0157, Item 9)
General Mechanic Tool Box (WP 0157, Item 24)
Personnel Required
91B, Light Wheel Vehicle Mechanic
INSPECTION
1. Visually inspect fuses, circuit breakers, and single pole double throw relays for damage affecting serviceability.
Inspect all sockets for corrosion.
2. Insect wiring inside dash panel for corrosion, damaged connectors and sockets, exposed wiring, and faulty
wiring mounting.
30
30
86
85
96
87
87
A
85
87A
87
WP0102F1
Figure 1. Relay Test Pin Identiication
END OF TASK
TEST
NOTE
Relays 2A through 2E (Figure 2, Item 2) are all tested using the same procedures and are
interchangeable. Connector pin numbers are stamped on the bottom of the relay next to the
relay plug pins.
Circuit Breaker and fuses (Figure 2, Item 3 through 8) are simply tested for continuity.
Relays
1. Disconnect battery negative cables (WP 0111).
2. Remove appropriate relay from socket holder.
3. Ohms test from pins 30 to 87A (Figure 1) for continuity.
4. Resistance measured should be less than 1 ohm.
5. Ohms test from pins 85 to 86 (Figure 1) for continuity.
6. Resistance should measure 85 ohms nominally.
7. Replace relay if either ohms test fails.
01221
