TM 5-2420-231-23-1
0029
Table 1. A/C System Pressure Indicator Fault - Continued.
029
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. Check A/C system pressures (WP
A/C System Pressure
A/C System Pressures Normal -
0364).
Proceed to Test Step 2.
Indicator Fault - Continued
A/C System Pressures High or Low -
Isolate fault using Heating and Air
Conditioning Troubleshooting
Procedures (WP 0030) and then
proceed to Test Step 6.
Test Step 2. Check for Faulty A/C
Pressure Relay.
1. Turn ignition switch to the off posi-
tion (TM 5-2420-231-10) and dis-
connect batteries (WP 0157).
2. Remove instrument panel front
cover (WP 0174).
3. Disconnect A/C pressure relay
(WP 0007, Figure 53) from front
console options wiring harness
connector (WP 0007, Figure 52).
4. Using a digital multimeter, test for
Continuity - Replace A/C pressure
continuity between A/C pressure
relay (WP 0007, Figure 53).
relay (WP 0007, Figure 53) termi-
Proceed to Test Step 6.
nals 30 and 87. There should be
No Continuity - Proceed to Test Step 3.
no continuity.
Test Step 3. Check for Shorted A/C
High-Pressure Switch.
1. Remove hood radiator screen and
bumpers (WP 0304).
2. Disconnect chassis options wiring
harness connector (WP 0007, Fig-
ure 40) from A/C high-pressure
switch (WP 0007, Figure 41).
3. Using a digital multimeter, test for
Continuity - Replace A/C high-
continuity between A/C high-pres-
pressure switch (WP 0363).
sure switch (WP 0007, Figure 41)
Proceed to Test Step 6.
terminals A and B. There should
No Continuity - Proceed to step 4.
be no continuity.
4. Using a digital multimeter, test for
Continuity - Proceed to Test Step 4.
continuity between chassis options
No Continuity - Proceed to Test Step 5.
wiring harness connector (WP
0007, Figure 40) terminals A and
B. There should be no continuity.
Test Step 4. Check for Shorted Side
Options Wiring Harness.
1. Remove front instrument panel
right-side cover (WP 0176).
0029-3