TROUBLESHOOTING THE M998 ELECT SYST. - OD1617 - LESSON 1/TASK 1
Disconnect leads 33A, 27G, and 58E from the coolant
temperature gage. Using the multimeter, check for battery voltage at
lead 27G with the rotary switch in the RUN position. Then check for
continuity from lead 58E to ground and continuity from lead 33A at
the coolant temperature gage to lead 33B at the temperature sending
If all leads test correctly, replace the coolant temperature
gage, following the procedures contained in paragraph 4-13 of the TM.
If any leads test incorrectly, repair the body wiring harness,
following the procedures contained in paragraph 4-62 of the TM.
the wiring harness cannot be repaired, notify IDS maintenance.
concerning troubleshooting this system, refer to figure 6 on the
Malfunction: HEATER MOTOR DOES NOT OPERATE OR ONLY OPERATES IN LO OR
If the heater motor
proceed to step 4.
Disconnect lead 57E at the heater motor.
Now, using a
multimeter, check for continuity between 57E and ground.
continuity is not present, repair the body wiring harness, following
the procedures contained in paragraph 4-62 of the TM.
If the body
wiring harness cannot be repaired, notify IDS maintenance.
Disconnect lead 400D from the heater motor.
multimeter, check for voltage with the heater motor switch in HI or
If voltage is present in both positions, replace the heater,
following the procedures in paragraph 10-59 of the TM. If voltage is
present in only one of the positions, or is not present at all,
proceed to step 3.