TM 5-2420-231-23-1
0031
Table 1. Heating, Ventilation, and A/C (HVAC) Blower Motor Does Not
Operate at One or More Speeds - Continued.
031
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
10. Using a digital multimeter, mea-
HVAC Blower Motor Does
Resistance 5.0 Ohms or Less and
sure resistance between high
Not Operate at One or More
HVAC Blower Motor Does Not
speed terminal and 12-V terminal
Speeds - Continued
Operate at Lowest Speed Setting -
(WP 0007, Figure 144). Resis-
Proceed to Test Step 3.
tance should be 5.0 ohms or less.
Resistance 5.0 Ohms or Less and
HVAC Blower Motor Does Not
Operate at Medium Speed Setting -
Proceed to Test Step 4.
Resistance 5.0 Ohms or Less and
HVAC Blower Motor Does Not
Operate at Highest Speed Setting -
Proceed to Test Step 5.
Resistance 5.0 Ohms or Less and
HVAC Blower Motor Does Not
Operate at Any Speed - Proceed to
Test Step 6.
Resistance Greater Than 5.0 Ohms at
Any Speed Setting - Replace blower
fan switch (WP 0172).
Proceed to Test Step 14.
Test Step 3. Test HVAC Blower Motor
Low-Speed Circuit.
1. Disconnect side console wiring
harness connector (WP 0007, Fig-
ure 130) from cab wiring harness
connector (WP 0007, Figure 129)
(WP 0170).
2. Using a digital multimeter, mea-
Resistance 5.0 Ohms or Less -
sure resistance between side con-
Proceed to step 3.
sole wiring harness connector (WP
Resistance Greater Than 5.0 Ohms -
0007, Figure 145) low-speed ter-
Replace side console wiring harness
minal and side console wiring har-
(WP 0170).
ness connector (WP 0007, Figure
Install blower fan switch (WP 0172).
130) terminal A3. Resistance
Proceed to Test Step 14.
should be 5.0 ohms or less.
3. Remove headliner and right-side
cover (WP 0346).
4. Remove right blower duct (WP
0350).
5. Disconnect cab wiring harness
connector (WP 0007, Figure 148)
from HVAC blower motor wiring
harness connector (WP 0007, Fig-
ure 149) (WP 0349).
0031-6