TM 10-8145-222-23
0079
REPAIR CONTINUED
Test Relay
NOTE
The plug and play socket type relay used in the MPC box is tested using a 9-volt DC
battery. When power is applied to the relay, an audible click will be heard if the coil is
operating correctly.
1. Test 9-volt battery to ensure it is charged.
2. Connect positive end of 9-volt battery (Figure 12, Item 1) to pin 86 on relay (Figure 12, Item 2).
3. Connect negative end of 9-volt battery (Figure 12, Item 3) to pin 85 on relay (Figure 12, Item 4).
4. Listen for an audible click indicating coil has energized.
If audible click is not heard, coil is bad. Replace relay.
5. If audible click is heard, check for continuity between pin 30 (Figure 12, Item 5) and pin 87a (Figure 12, Item 6)
on relay.
If there is continuity, relay is good. Reinstall relay.
If there is no continuity, relay is defective. Replace relay.
Figure 12. Relay Test.